Physics. Dynamics and Space Question Booklet 3 Space

Transcription

1 Physics Dynamics and Space Question Booklet 3 Space

2 Dynamics and Space Speed of light in materials Speed of sound in materials Material Speed in m/s Material Speed in m/s Air 3 x 10 8 Aluminium Carbon dioxide 3 x 10 8 Air 340 Diamond 1 2 x 10 8 Bone Glass 2 0 x 10 8 Carbon dioxide 270 Glycerol 2.1 x 10 8 Glycerol Water 2 3 x 10 8 Muscle Steel Gravitational field strengths Tissue Gravitational field strength on the surface in N/kg Water Earth 10 Specific heat capacity of materials Jupiter 26 Material Specific heat Mars 4 capacity in J/kg o C Mercury 4 Alcohol Moon 1 6 Aluminium 902 Neptune 12 Copper 386 Saturn 11 Glass 500 Sun 270 Glycerol Venus 9 Ice Uranus 11 7 Lead 128 Pluto 4 2 Silica Specific latent heat of fusion of materials Material Specific latent heat of fusion in J/kg Alcohol 0 99 x 10 5 Water Steel 500 Melting and boiling points of materials Material Melting point in o C Boiling point in o C Aluminium 3 95 x 10 5 Alcohol Carbon dioxide 1 80 x 10 5 Aluminium Copper 2 05 x 10 5 Copper Glycerol 1 81 x 10 5 Glycerol Lead 0 25 x 10 5 Lead Water 3 34 x 10 5 Turpentine Specific latent heat of vaporisation of materials SI Prefixes and Multiplication Factors Prefix Symbol Factor Material Sp.l.ht vap(j/kg) giga G =10 9 Alcohol 11 2 x 10 5 mega M =10 6 Carbon dioxide 3 77 x 10 5 kilo k =10 3 Glycerol 8 30 x 10 5 milli m =10-3 Turpentine 2 90 x 10 5 micro =10-6 GMV Science. Photocopiable only by the purchasing institution 2

3 Weight, Thrust and Acceleration In this section you can use the equation: unbalanced force = mass x acceleration also written as F = ma where F = unbalanced force in newtons (N) m = mass in kilograms (kg) a = acceleration in metres per second per second (m/s 2 ). Helpful Hint When a spacecraft is in space the only force acting on it is its engine thrust. engine thrust (F) 1. Find the missing values in the table. Force (N) Mass (kg) Acceleration (m/s 2 ) (a) 700, (b) 45, (c) (d) 3,600, (e) 10,000 80,000 (f) 2,600,000 2,000, The engine of a space shuttle can produce a thrust of N. The mass of the shuttle is 8 x 10 5 kg. Calculate the acceleration of the shuttle in space. 3. What engine thrust must be produced by a rocket of mass 3 x 10 6 kg in order to produce an acceleration of 1 4 m/s 2 in space? 4. The maximum engine thrust of a spacecraft is 2 4 x 10 7 N and this produces an acceleration of 12 m/s 2 in space. What is the mass of the spacecraft? GMV Science. Photocopiable only by the purchasing institution 3

4 Weight, Thrust and Acceleration 5. An engine force of 160 kn is used to slow down a shuttle in space. If the mass of the shuttle is kg what is its rate of deceleration? Helpful Hint To find the acceleration, a, of an object during a vertical take-off you will need to calculate the unbalanced force acting on the object first. Example thrust 1 st. Unbalanced force = thrust weight 2 nd a = F (where F = unbalanced force) m weight 6. Use the three stages outlined in the example above to find the missing values in the following table. Assume that each mass is in the Earth s gravitational field. Mass (kg) Weight (N) Thrust (N) (a) (b) (c) ,000 (d) 50, ,000 (e) 70, ,000 (f) 76, ,800 Unbalanced Force (N) Acceleration (m/s 2 ) GMV Science. Photocopiable only by the purchasing institution 4

5 Weight, Thrust and Acceleration 7. A water rocket has a mass of 0 8 kg and is launched in a school playground with an initial upwards thrust of 12 N. (a) What is the weight of the water rocket in the playground? (b) What is the initial acceleration of the rocket in the playground? (c) If this water rocket were launched from the moon, what would be its initial acceleration? (Remember to find the new weight first!) 8. A rocket is launched from Earth with an initial acceleration of 2 5 m/s 2. The mass of the rocket is kg. (a) Calculate the unbalanced force acting on the rocket during its launch. (b) What is the weight of the rocket? (c) Calculate the engine thrust of the rocket. (d) What engine thrust would be required to launch this rocket from the moon with the same acceleration? 9. Calculate the acceleration of the following objects. (a) A model rocket of mass 30 kg being launched from Earth with an engine thrust of 800 N. (b) A satellite in space whose mass is 1,800 kg and whose engine force is 4 68 kn. (c) A kg shuttle travelling at 50 m/s in space. (d) A toy rocket of mass 1 5 kg whose engine stopped while the rocket was in mid air. (e) A spaceship of mass 4 x 10 7 kg lifting off from Saturn with an engine thrust of 9 x 10 8 N. (f) A rocket of mass 2 2 x 10 6 kg being launched from Neptune with an engine thrust of 4 4 x 10 7 N. GMV Science. Photocopiable only by the purchasing institution 5

6 Weight, Thrust and Acceleration 10. A space shuttle has a weight of 1 8 x 10 7 N on Earth. Its engines produce a thrust of 2 7 x 10 6 N during part of its journey through space. (You will need to refer to the data sheet on page 2 for parts of this question.) (a) Calculate the mass of the shuttle. (b) What is the acceleration of the shuttle in space while its engine thrust is 2 7 x 10 6 N? (c) Could the shuttle have been launched from Earth with this engine thrust of 2 7 x10 6 N? Explain your answer. (d) The engine thrust was 2 7 x 10 7 N during the launch from Earth. What was the acceleration of the shuttle during its launch? (e) If a similar shuttle was launched from Venus with an engine thrust of 2 7 x 10 7 N, what would be the acceleration of this shuttle during lift off? (f) What engine thrust would be required in order to launch this shuttle from Jupiter with an acceleration of 5 m/s 2? GMV Science. Photocopiable only by the purchasing institution 6

7 Cosmology Questions 1 1. What is a solar system? 2. The moon orbits the Earth, it is an example of a natural 3. List the eight planets in our solar system, in order, from closest to the sun to furthest away from the sun. 4. Which of the planets is the largest? 5. Which planets have no moons? 6. What is the difference between the four planets nearest the sun compared to the four furthest away from the sun? 7. What is the description now given to describe Pluto? 8. What is a star mostly made of? 9. What is a galaxy? 10. What is the name of our galaxy? 11. What is the name given to the unit of distance typically used in space? 12. What is the name of the nearest star to the sun and how far away is it? 13. What is the name given to the start of the Universe? 14. What is meant by the Universe? 15. Give one piece of evidence that supports the theory behind the start of the Universe? 16. What estimate do cosmologists put on the age of the Universe? 17. List three conditions which must exist for life, as found on Earth, to exist on another planet. 18. What is the name given to a planet which orbits around another star (but not our Sun)? 19. What is the name given to the area where planets which might be habitable are found? 20. List three ways we can explore space. SIC Physics Fevelopment Group I McI 7

8 Cosmology Questions 2 GMV Science. Photocopiable only by the purchasing institution 8

9 Cosmology Questions 2 Clues down 1. Jupiter--- Mars are planets Centauri is the nearest star outwith our Solar System. 3. The closest star to Earth. 4. A useful object for star gazing. 5. We see these because of the different frequencies in white light. 7. The moon is a natural satellite of this planet. 8. This keeps our feet on the ground! 10. This large lens in a telescope creates the image of a star. 14. This quantity is measured in kilograms and does not change from planet to planet nm is the wavelength of this light. 16. The Universe is the name given to - -- matter and space. Clues across 2. This object can separate white light into its various colours. 4. We could describe ourselves as this compared to the Universe. 6. The number of stars in our Solar System. 8. A cluster of stars. 9. The sun will not keep burning for Paths for planets around the Sun. 12. Here the gravitational field strength is virtually zero. 13. This fictional character was not from Earth.! 17. Obtained by mixing red, green and blue. 18. The Sun and its nine planets. GMV Science. Photocopiable only by the purchasing institution 9

10 Distances in Space 1 Distances in Space In this section you can use the following equation: v = d t where: v = average speed in meters per second (m/s) d = distance travelled in metres (m) t = time taken in seconds (s). Helpful Hint Because distances in space are so large, astronomers use light years to measure distance. One light year is the distance light will travel in one year. Light travels at 3 x10 8 m/s. 1. How far is a light year? 2. The star Vega is 27 light years from earth. How far away is Vega in metres? 3. The star Pollux is 3 78 x m from earth. How far is this in light years? 4. The star Beta Centauri is 300 light years from earth. How long does it take light to travel from this star to the earth? 5. An astronomer on Earth views the planet Pluto through a telescope. Pluto is 5,763 x 10 6 km from earth. How long did it take for the light from Pluto to reach the telescope? 6. Our galaxy, the Milky Way, is approximately 100,000 light years in diameter. How wide is our galaxy in kilometres? 7. The nearest star to our solar system is Proxima Centuri which is 3 99 x10 16 m away. How far is this in light years? 8. Andromeda (M31) is the nearest galaxy to the Milky Way and can just be seen with the naked eye. Andromeda is 2 1 x m away from the Milky Way. How long does it take for light from Andromeda to reach our galaxy? GMV Science. Photocopiable only by the purchasing institution 10

11 Distances in Space 1 9. The Sun is the nearest star to the planet Earth. It takes light 8 3 minutes to reach us from the Sun. Use this information to find out the distance from the Earth to the Sun in kilometres? 10. Sir William Herschel, an amateur astronomer, discovered the planet Uranus in March Uranus is x 10 6 km away from the sun. How long does it take for sunlight to reach Uranus? GMV Science. Photocopiable only by the purchasing institution 11

12 Distances in Space 2 Given that the speed of light in a vacuum is 3 x 10 8 m/s 1. How far does light travel in a. 1 second b. 1 minute c. 1 hour d. 1 day e. 1 year 2. If it takes 9 years for light from Sirius to reach Earth How far away is Sirius in metres? 3. As the Sun is 1.5 x m from Earth. How long does it take light from the Sun to reach Earth? 4. The moon is 3.84 x 10 8 m from Earth. How long does it take light to travel from the Moon to Earth? 5. Uranus is 2.7x m from Earth. How long will it take light to travel from Earth to Uranus? 6. Proxima the nearest other star to the Earth is 4.07 x m away. How many light years is this? 7. The Andromeda Galaxy is 1.9 x m away. What is this in light years? 8. Ursa Major is a constellation that is 1x 10 7 light years from Earth. How far is this in kilometres? SIC Physics Fevelopment Group I McI 12

13 Space Exploration 1. Space exploration is an ever developing area of science. As a result of the many different space programs across the world, technology is continually advancing. Many of the materials and equipment designed have had an impact on our daily lives. Name one material or piece of equipment which was originally developed for space, describe its use in space and give information about its use in everyday life. 2. As well as the benefits of the space program there is a down side Space Junk! NASA currently monitors over 13,000 man-made objects orbiting the Earth larger than 10cm in diameter this has increased from 9,000 in It estimates that there are millions of much smaller objects and that the total mass is about 5500 tonnes. (a) What are the large man-made object orbiting Earth? (b) It has even been suggested that nuclear waste could be put on the moon. State whether or not you think this is a good idea, giving reasons for your opinion. 3. The first satellite Sputnik 1 was launched on 4/10/1957. There are now a very large number of satellites orbiting the Earth using cutting edge technologies to collect signals from tracking devices, to take photographs and temperature readings as well as many other functions. (a) What effect does changing the height above the Earth s surface have on the period of the satellite? (b) How are satellites used in weather forecasting? (c) How are they used in environmental monitoring? (d) What is GPS and what is it used for? (e) What is a geostationary satellite and how many are required for a global communications network? (f) Find out about satellite tracking:- i. Why would you want to track vehicles? ii. Why would you want to track animals? SIC Physics Fevelopment Group JM 13

14 Space Travel 1. Explain why the speed of a spacecraft, travelling in outer space, is constant even although its engines are switched off? 2. How do spacecraft travelling in outer space change direction and where does the energy come from? 3. Our two nearest planets are Mars and Venus. a) If the closest Mars comes to the Earth is 65 million km calculate how long it would take for a rocket travelling at 2900 m/s to reach it? b) How long would it take to send a message to reach Mars at this time? c) The time it takes to reach a distant planet such as Mars raises challenges for manned missions. i) What effect does weightlessness have on the human body? ii) Can you list some of the concerns Mission Control would have and come up with suggestions for solutions? d) There have been a number of unmanned missions to Mars called Mars Rovers. What were the names of the different rovers and when did they land on Mars? 4. The closest distance between the Earth and Saturn is 1.2 x 10 9 km. How long would it take a probe orbiting Saturn to send a signal to Earth? 5. Voyager 1 and Voyager 2 were launched in (a) How are they powered, how do they change direction and where does the energy needed to send transmissions come from? (b) After 12 years Voyager 2 shot past Neptune at a distance of approximately 4.35 x 10 9 km from Earth. How long would it have for a signal to reach the Earth? SIC Physics Fevelopment Group JM 14

15 Re-entry 1 Re - Entry In this section you can use all of the following equations: E k = 1mv 2 2 E h = cm T E w = F x d where E k = kinetic energy (J) E h = heat energy (J) E w = work done (J) m = mass (kg) v = speed (m/s) c = specific heat capacity (J / kg o C) T = change in temperature ( o C) F = force (N) d = distance (m). Helpful Hint Energy can not be created or destroyed. It can be changed from one form into another. When an object re-enters the Earth s atmosphere it heats up. Some or all of its kinetic energy changes to heat energy as work is done against friction. The shuttle has heat resistant tiles covering its body to stop it burning up as it re-enters the atmosphere. heat resistant tiles In order to stop the shuttle when it touches down, work must be done by friction forces in the brakes to change all its kinetic energy into heat energy. GMV Science. Photocopiable only by the purchasing institution 15

16 Re-entry 1 1. A small piece of metal of mass 2 kg falls from a satellite and re-enters the Earth s atmosphere at a speed of m/s. If all its kinetic energy changes to heat calculate how much heat is produced. 2. How much work must be done by the brakes on a shuttle of mass 2 x10 6 kg to bring it to rest if it lands with a touch down speed of 90 m/s? 3. The space shuttle Columbia re-entered the Earth s atmosphere at a speed of 8000 m/s and was slowed down by friction to a speed of 200 m/s. The shuttle has a mass of 2 x10 6 kg. (a) How much kinetic energy did the shuttle lose? (b) How much heat energy was produced during this process? 4. A shooting star is a meteoroid that enters the Earth s atmosphere and is heated by the force of friction which causes it to glow. A certain meteoroid has a mass of 30 kg and enters the atmosphere at a speed of 4000 m/s. Its specific heat capacity is 600 J/kg o C. (a) Calculate the heat energy produced when all the meteoroids kinetic energy is converted to heat. (b) Calculate the rise in temperature of the meteoroid as it re-enters the atmosphere. 5. A small spy satellite of mass 70 kg is constructed from a metal alloy of specific heat capacity 320 J/kg o C. The satellite has a short lifetime of two weeks before it re-enters the Earth s atmosphere at a speed of 5000 m/s. (a) Calculate how much heat energy is produced when all the satellites kinetic energy changes to heat energy. (b) Calculate the theoretical rise in temperature of the satellite. GMV Science. Photocopiable only by the purchasing institution 16

17 Re-entry 1 6. The nose section of the shuttle is covered with 250 kg of heat resistant tiles which experience a rise in temperature of 1400 o C during the shuttle s journey back through the Earth s atmosphere. The shuttle is slowed from m/s to 100 m/s during this part of the journey. shuttle enters Earth s atmosphere v = m/s United St ate s v = 100 m/s (a) How much kinetic energy does the nose of the shuttle lose? (b) How much heat energy is produced at the nose during re-entry? (c) Calculate the specific heat capacity of the material used to make the nose tiles. 7. A multistage rocket jettisons its third stage fuel tank when it is empty. The fuel tank is made of aluminium and has a mass of 4000 kg. (specific heat capacity of aluminium is 900 J/kg o C) (a) Calculate the kinetic energy lost by the fuel tank as it slows down from m/s to m/s during its journey through the atmosphere. (b) How much heat energy is produced? (c) Calculate the rise in temperature of the fuel tank. 8. The command module of an Apollo rocket returns to Earth at a speed of 30 km/h. During its journey through the atmosphere it is slowed to a speed of 10 km/h. The mass of the module is kg. (a) Calculate the loss in kinetic energy of the command module. (b) How much work is done by the frictional forces which slowed it down? GMV Science. Photocopiable only by the purchasing institution 17

18 Re-entry 1 9. Re-entry for a certain shuttle begins 75 miles above the Earth s surface at a speed of 10 km/s. It is slowed to a speed of 100 m/s by frictional forces during which time it has covered a distance of 4 x10 7 m. The mass of the shuttle and its payload is 2 4 x 10 6 kg. (a) Calculate the loss in kinetic energy of the shuttle. (b) How much work is done by friction? (c) Calculate the average size of the frictional forces exerted by the atmosphere on the shuttle as it slows down. 10. At touch down a shuttle is travelling at 90 m/s. The brakes apply an average force of 4 x 10 6 N in total to bring the shuttle to a stand still. The mass of the shuttle is 2 x 10 6 kg. (a) How much kinetic energy does the shuttle have at touch down? (b) How much work must be done by the brakes to stop the shuttle? (c) Calculate the length of runway required to stop the shuttle. GMV Science. Photocopiable only by the purchasing institution 18

19 Re-entry 2 1. The Space Shuttle orbits the earth at 10 Km/s. It then re-enters the Earth s atmosphere and comes in to land. (a) During re-entry it does not fire any engines to slow itself down. What causes its speed to be reduced? (b) What happens to the energy of the space shuttle when it re-enters the Earth s atmosphere? (c) The Space shuttle is covered with heat resistant tiles. Why are the tiles on the underside thicker than those on the upper surface of the shuttle? 2. A meteor of mass 75 kg enters the Earth s atmosphere at 30 km/s. Explain what is likely to happen to the meteor before it reaches the surface of the Earth? SIC Physics Development Group AF 19

20 Re-Entry 3 1. When spacecraft, meteorites and space junk enter the Earth s atmosphere they are moving very quickly and have a large amount of kinetic energy. (a) What happens to this kinetic energy when they come into contact with the atmosphere? (b) How does this effect meteorites and how can we see them from the surface of the Earth? 2. Explain why designers have to make manned spacecraft capable of withstanding very high temperatures and what thermal protection systems are used. 3. Find out how astronauts and spacecraft were protected on re-entry:- (a) (b) In the early space programmes. In the space shuttle missions. 4. An aluminium section of a rocket thruster weighs 0.9kg. It returns to Earth at a speed of 5000m/s. If we assume that all its kinetic energy is changed into heat on entry into the atmosphere, find:- (a) It s rise in temperature. (for aluminium c = 900J/kgºC) (b) Explain why such small sections of a space craft would be unlikely to be found on the Earth s surface. 5. A satellite of mass of mass 70kg orbits the Earth at a speed of 4000m/s. The satellite is mainly made from a metal alloy of specific heat capacity 310 J/kgºC. (a) Calculate the kinetic energy of the satellite when in orbit. (b) Calculate the change in temperature of the satellite if all the kinetic energy is changed into heat as it returns to Earth. (c) Suggest why in practice this temperature would not be reached. SIC Physics Development Group JM 20

21 Projectiles 1 1. The motion of a projectile can be thought of as comprising two independent motions. (a) Describe the horizontal component of motion. (b) Describe the vertical component of motion. (c) What assumption do we make in order to do the calculations? 2. An Osprey is flying horizontally at a speed of 15 m/s when it drops the fish it is carrying into the loch below. The fish hits the water 2 seconds later. (a) Calculate the height the osprey was flying at when it dropped the fish. (b) Assuming that the Osprey does not change its speed or direction, where is it in relation to the fish when the fish hits the water. SIC Physics Development Group AF 21

22 Projectiles 2 Helpful Hint In this section you can make use of the fact that any projectile path can be split into separate parts - horizontal and vertical. To solve any projectile problem it is necessary to use the formula which applies to each of these directions. Horizontally Velocity is constant ( a = 0 m/s 2 ) v = d t where v = average horizontal velocity in metres per second (m/s) d = horizontal distance travelled in metres (m) t = time taken in seconds (s). Vertically Acceleration due to gravity Where a = acceleration due to gravity in metres per second per second (m/s 2 ) u = initial vertical velocity in metres per second (m/s) v = final vertical velocity in metres per second (m/s) t = time taken in seconds (s). To calculate the vertical distance travelled during any projectile journey you must draw a speed time graph for the journey and use: distance travelled = area under speed time graph. 1. A stone is kicked horizontally at 20 m/s from a cliff top and lands in the water below 2 seconds later. 20 m/s Calculate : (a) the horizontal distance travelled by the stone (b) the final vertical velocity (c) the vertical height through which the stone drops. GMV Science. Photocopiable only by the purchasing institution 22

23 Projectiles 2 2. A parcel is dropped from a plane and follows a projectile path as shown below. The horizontal velocity of the plane is 100 m/s and the parcel takes 12 seconds to reach the ground. 100 m/s Calculate : (a) the horizontal distance travelled by the parcel (b) the final vertical velocity of the parcel as it hits the ground (c) the height from which the parcel was dropped. 3. Sand bags are released from an air balloon while it is at a fixed height. The bags follow a projectile path because of strong winds. 30 m/s The bags have an initial horizontal velocity of 30 m/s and land on the ground 10 seconds later. Calculate: (a) the horizontal distance travelled by the sand bags (b) their final vertical velocity. GMV Science. Photocopiable only by the purchasing institution 23

24 Projectiles 2 4. A satellite is launched during a practice simulation. The satellite is given a horizontal velocity of 400 km/s and crashes 200 seconds later. 400 km/s practise launch pad Calculate : (a) the horizontal distance travelled by the satellite (b) the final vertical velocity of the satellite (c) the height from which the satellite was launched. 5. An archer fires an arrow and aims to hit a target 50 metres away. The arrow is launched with a horizontal velocity of 100 m/s. 100 m/s (a) What is the time of flight of the arrow? (b) Calculate the final vertical velocity of the arrow. (c) By how much does the arrow miss the target? 6. A golfer strikes a golf ball and it follows a projectile path as shown below. (a) What is the vertical velocity of the ball at its maximum height? (b) What is the horizontal component of the velocity if the ball takes 4 seconds to travel 400 metres? GMV Science. Photocopiable only by the purchasing institution 24

25 Projectiles 2 7. While on the moon an astronaut throws a rock upwards and at an angle. The path of the rock is shown below. (a) What is the vertical velocity of the rock at its maximum height? (b) How long does the rock take to reach its maximum height if it has an initial vertical velocity of 20 m/s? (Remember! On the moon a = 1 6 m/s 2 ) 8. Part of the space flight of a shuttle is represented in the velocity time graphs below. (a) Horizontal motion (b) Vertical motion Speed in m/s Speed in m/s 0 Time in s Time in s Use the graphs to find out how far the shuttle travels both horizontally and vertically in the 30 second journey. GMV Science. Photocopiable only by the purchasing institution 25

26 Projectiles 2 9. During take off from Mars one of the boosters on a rocket fails causing the rocket to follow a projectile path rather than a vertical one. The speed time graphs for a 20 second interval immediately after the booster failed are shown below. (a) Horizontal motion (b) Vertical motion Speed Speed in m/s in m/s Time in s 0 20 Time in s Use the graphs to calculate: (a) the horizontal distance travelled during take off (b) the deceleration in the vertical direction during the first 20 seconds (c) the vertical distance travelled. 10. A stunt motor cyclist tries to beat the record for riding over double decker buses. He leaves the start position with a horizontal velocity of 35 m/s and lands 2 4 seconds later. Calculate : (a) the horizontal distance travelled by the cyclist (b) the final vertical velocity of the motor cycle as it touches the ground (c) the height of the platform. GMV Science. Photocopiable only by the purchasing institution 26

27 Projectiles 3 1. A stone thrown horizontally from a cliff lands 24 m out from the cliff after 3 s. Find: a) the horizontal speed of the stone b) the vertical speed at impact. 2. A ball is thrown horizontally from a high window at 6 m/s and reaches the ground after 2 s. Calculate a) the horizontal distance travelled b) the vertical speed at impact. 3. An aircraft flying horizontally at 150 m/s, drops a bomb which hits the target after 8 s. Find: a) the distance travelled horizontally by the bomb b) the vertical speed of the bomb at impact c) the distance travelled horizontally by the aircraft as the bomb fell d) the position of the aircraft relative to the bomb at impact. 4. A ball is projected horizontally at 15 m/s from the top of a vertical cliff. It reaches the ground 5 s later. For the period between projection until it hits the ground, draw graphs with numerical values on the scales of the ball s a) horizontal velocity against time b) vertical velocity against time c) From the graphs calculate the horizontal and vertical distances travelled. 5. In the experimental set-up shown below, the arrow is lined up towards the target. As it is fired, the arrow breaks the circuit supplying the electromagnet, and the target falls downwards from A to B. target A electromagnet holds target in place B a) Explain why the arrow will hit the target. b) Suggest one set of circumstances when the arrow would fail to hit the target (you must assume it is always lined up correctly). Physics: Mechanics and Heat (Int 2) Student Material 27

28 Satellite Questions 1. What part of the electromagnetic spectrum is used to communicate with satellites? 2. What speed does this radiation travel at? 3. Why can some electromagnetic frequencies not be used when sending a signal from Earth to an orbiting satellite? 4. Fill in the gaps in the following paragraph. Geostationary satellites orbit above the. Geostationary satellites always remain at the point above the earth s surface. Geostationary satellites orbit every 24 hours. Other satellites complete several every 24 hours. Other satellites operate at a height than Geostationary satellites. 5. Copy and complete the above table by filling in the gaps choosing from the following: 390km 28 days km 1000km km 90 minutes 12 hours 100 minutes Type of Satellite Approximate Height above the earth (km) Time taken for 1 orbit International Space Station Polar Orbit GPS Fleet Geostationary hours The Moon Notes Zero gravity Lab Monitoring Land use, Weather Navigation aid Worldwide communication Broadcasting TV Gives us the Earths tides. SIC Physics Development Group PB 28

29 Satellite Questions 6. An aerial cannot pick up strong enough signals from a satellite. In order to bring radio signals to a focus a reflector must be used. 7. In short; what do parabolic mirrors do to electromagnetic radiation coming from far away? 8. By adding an appropriate shaped mirror complete the following diagram to show how signals are brought into focus. 9. Parabolic mirrors are used in torches and headlamps draw a diagram to show how they help to form a beam of light that can be directed. 10. Radio telescopes use large parabolic reflectors, what are they used for? 11. High frequency radio signals are sent from the USA to Britain. The signals are received by a ground station in Cornwall. (a) Describe what happens to the signal after it leaves the American ground station. (b) Weather forecasters on television show us detailed pictures of rain clouds over Britain. How is this kind of information gathered? SIC Physics Development Group PB 29

30 Satellite Questions 12. An army unit on military exercise at the Earth's equator have positioned a satellite dish as shown. Dish Aerial Aerial Curved reflector During their stay they find there is no need to change the position of the dish, which is pointing vertically upward. Communications are good and are never interrupted. (a) Why is there no need to continually alter the position of the satellite dish? (b) What name is given to the type of satellite being used? (c) What is the purpose of the curved reflector behind the aerial? 13. Why can radio waves not be used to carry television signals from America to Britain using land based transmitters and receivers? 14. A Satellite is used to relay the signal from America to Britain. The distance between the satellite and America is km which is the same as the distance between Britain and the satellite. Calculate the time taken for the signal to be sent from America to Britain. SIC Physics Development Group PB 30

31 Satellite Questions 15. Mrs Brown looked out of her window and saw a satellite-receiving dish being installed on her neighbour's wall. The installation engineers take great care to point the receiver towards a geostationary satellite. a) What is a satellite? b) Explain what is meant by geostationary. c) Figure 2 shows signals from the satellite coming towards the curved dish on the wall. Copy and complete figure 2 to show what happens to the signals after they hit the curved dish. Wall [ figure 2 d) How do the signals get from the receiving dish to the T.V. in the house? e) It is recommended that people living northern Scotland should use a 85-centimetre diameter dish, while those living in south-east England only need a 55-centimetre diameter dish. i) State one advantage of having an 85 centimetre dish rather than a 55 centimetre dish. ii) What does this suggest about the satellite signals received in northern Scotland SIC Physics Development Group PB 31

32 Ray Diagrams Helpful Hint You may have noticed that many of the images produced by convex lenses were on the opposite side of the lens from the object. These images are called real images. Sometimes, however, an image cannot be formed in this way because the rays spread out after passing through the lens. In this case we must extend the ray lines backwards until they meet. Example image f object f lens This type of image, which is formed on the same side of the lens as the object is called a virtual image. Remember the rules for drawing ray diagrams: 1. a ray from the tip of the object parallel to the axis passes through the focal point of the lens. 2. a ray from the tip of the object to middle of the lens continues through the lens in the same direction. 1. An object is placed 3 cm from a lens which has a focal length of 2 cm. The object is 1 cm high. Using a suitable scale, copy and complete the ray diagram below. (You may find it useful to use graph paper!) 1 cm high lens 3 cm 2 cm (a) How far from the lens is the image produced? (b) Is the image inverted or upright? (c) Is the image real or virtual? GMV Science. Photocopiable only by the purchasing institution 32

33 Ray Diagrams 2. A magnifying glass produces an image which is described as virtual, magnified and upright. A 1 cm high object is placed 2 cm from a magnifying lens whose focal length is 3 cm. (a) Copy and complete the ray diagram below to show how the image is formed. 1 cm high lens 2 cm 3 cm (b) Explain why the image is described as virtual, magnified and upright. 3. A 1 cm high object is placed 5 cm from a lens which has a focal length of 2 cm (a) Use a ray diagram to find out what kind of image is formed (i.e. real or virtual? magnified, diminished or same size? inverted or upright?) (b) The same object is moved to a distance of 4 cm from the lens. Describe the image which is now formed. (You will need to draw a new ray diagram!) (c) The object is again moved - this time to a distance of 1 5 cm from the lens. Describe what happens to the image now. 4. A magnifying glass, which has a focal length of 1 cm, is used to examine some small objects. Each object is placed 0 5 cm from the lens. By drawing ray diagrams, to an appropriate scale, find out the size of the image produced by each of the following objects. (a) A printed letter which is 4 mm high. (b) A 2 mm grain of rice. (c) A 5 mm pearl. 5. A man creates an image of a fuse using an 8 cm lens. The fuse is 2 cm high and is positioned at a distance of 4 8 cm from the lens. (a) Draw a ray diagram in order to find out the height of the image produced. (b) How far was this image from the lens? GMV Science. Photocopiable only by the purchasing institution 33

34 Cosmology Questions 3 1. d o =10cm f o =80cm Telescope 1 f e = 8 cm d o =15cm f o =120cm Telescope 2 f e = 2 cm a) Which telescope collects most light? b) Which telescope will have the brighter image? c) If the objective lens has a focal length f o and the eyepiece lens a focal length f e, the length of the telescope is given by f o + f e. Which is the longer telescope? d) The magnification of a telescope is calculated using f o /f e i) What is the magnification of telescope 1 ii) What is the magnification of telescope 2 2. If a telescope has an objective lens with focal length 105cm and an eyepiece lens with focal length 1.5cm a) What is the length of the telescope? b) What is the magnification of the telescope? 3. If a telescope has an objective lens with focal length 65cm and an eyepiece lens with focal length 13 cm a) What is the length of the telescope? b) What is the magnification of the telescope? SIC Physics Development Group IM 34

35 Cosmology Questions 3 You have been give a spectrum reference sheet showing the spectrum obtained from various elements using a diffraction spectrometer. SIC Physics Development Group IM 35

36 Cosmology Questions 3 a) Use the reference sheet to identify elements A and B b) Use the reference sheet to identify the elements present in spectra C, D, E and F. c) Which elements are present in all four spectra C, D,E and F SIC Physics Development Group IM 36

37 Revision 1. Stars and galaxies emit radiation at many different frequencies in the electromagnetic spectrum. By collecting these signals astronomers can learn a lot about our universe. (a) Copy and complete the diagram of the electromagnetic spectrum shown below. Gamma rays UV IR TV waves (b) Which waves have the longest wavelength? (c) It takes radio waves from the galaxy Andromeda 2 2 million years to reach us. How far away is Andromeda in kilometres? (one year = 365 days) (d) Name a detector for each type of electromagnetic radiation in the spectrum. Light gathered from the stars can be split into spectra using a prism or a diffraction grating. This allows astronomers to gather a great deal of information about the stars. (e) What is the name given to the type of spectrum shown below? (f) Identify two elements present in this spectrum using the information below. GMV Science. Photocopiable only by the purchasing institution 37

38 U S Revision 2. Magnifying glasses are used in the eyepieces of refracting telescopes. One such telescope used to observe stars is shown below. eyepiece X Y light from star (i) What names are given to the telescope parts labelled X and Y on the diagram? (ii) Explain why part Y should have a large diameter. (iii) What is the purpose of the eyepiece in this telescope? 3. The Chinese first used rockets in the thirteenth century. These rockets used a type of gunpowder to fuel them. Most modern rockets are liquid fuelled but work on the same principle as the early rockets. (a) Explain using Newton s third law how a rocket engine propels a rocket forward. (b) A multistage rocket of mass 1 6 x 10 5 kg is preparing for lift off from Earth. The rocket engines provide a constant thrust of 2 2 x 10 6 N. A Calculate the initial acceleration of the rocket. (c) The acceleration of the rocket increases as it burns up fuel even though the thrust provided by the engine remains constant. Explain why. (d) Once in space the rocket engines are switched off. Describe the motion of the rocket now and explain its motion in terms of Newton s laws. GMV Science. Photocopiable only by the purchasing institution 38

39 Revision The graph below shows how the speed of a different rocket varied with time after lift off. (e) Calculate the initial acceleration of the rocket. (f) How far did the rocket travel in the 500 seconds shown 4. In the future travel to other planets may be possible. During a virtual reality flight, Spacekid observes the following : A B C D Walking on the moon seemed effortless but on Jupiter his boots felt as though they were being held down. Take off from Earth needed less engine thrust than take off from Neptune. Rocket motors could be switched off during interplanetary flight. When a 1 2 kg hammer was dropped on Saturn its time and vertical velocity were recorded as: Time (s) Velocity (m/s) (a) Explain observation A. (b) Draw a diagram showing the forces acting on a rocket during take off. Use the values of g from the data sheet on page 24 to explain, in terms of the forces acting on the rocket, why take off requires more engine thrust on Neptune. (c) If the rocket has a mass of 3 x 10 7 kg and the engine thrust is 3 9 x 10 8 N, calculate the acceleration of the rocket at take off from Earth. GMV Science. Photocopiable only by the purchasing institution 39

40 Revision (d) Explain observation C (e) Use the results from D to plot a speed time graph of the hammer falling on Saturn. (f) From the graph: (i) How far did the hammer fall (ii) Calculate the gravitational field strength on Saturn. (g) Spacekid has a mass of 40 kg. On which planet, Earth or Saturn, is he heavier? Justify your answer. 5. A space shuttle of mass 2 x 10 6 kg was travelling with a speed of m/s as it entered the Earth s atmosphere. The speed of the shuttle dropped to 100 m/s at touch down, at which point the brakes were applied, bringing the shuttle to rest. (a) Explain why the speed of the shuttle decreased from m/s to 100 m/s before the brakes were applied. (b) How much kinetic energy did the shuttle lose before the brakes were applied? (c) How much heat energy was created as the shuttle speed dropped from 9000 m/s to 100 m/s? (d) The shuttle was covered with special heat-resistant tiles. Why was this necessary? (e) The specific heat capacity of the heat-resistant material used in the tiles is 35,700 J/kg 0 C. The temperature of the tiles should increase by no more than 1,300 0 C during re-entry. What mass of tiles would be required to absorb all of the heat energy produced? (f) Explain why in practice the mass of the tiles was less than calculated in part (e). (g) How much work was done by the brakes to bring the shuttle to rest? GMV Science. Photocopiable only by the purchasing institution 40

41 Revision 6. Use the information on the data sheet to answer the following: (a) On which planet would a 3 kg rock fall fastest. Explain your answer. (b) On which planets would the same rock fall most slowly. Explain your answer. A rock is projected on Saturn as shown. 20 m/s (c) Use your knowledge of how the gravitational field strength affects falling objects to copy and complete the following table of vertical velocity and time for the rock falling on Saturn.. Time (s) Vertical velocity 0 (m/s) (d) Draw a speed time graph for both the horizontal and vertical motion of the rock within five seconds of being thrown. (e) Use the graphs to calculate both the horizontal and vertical distance travelled by the rock in the first three seconds. (f) How long will the rock take to reach a vertical speed of 132 m/s GMV Science. Photocopiable only by the purchasing institution 41

42 Numerical Answers to Questions Weight,Thrust & Acceleration 1.(a) 1.4 x 10 6 N (b) N (c) kg (d) 3.6 x 10 8 kg (e) m/s 2 (f) 1.33 m/s m/s x 10 6 N 4. 2 x 10 6 kg m/s 2 6.(a) 30 ; 10 (b) ; 9.5 (c) ; ; 3.33 (d) ; ; 1 (e) ; ; 2 (f) ; ; (a) 8 N (b) 5 m/s 2 (c) 13.4 m/s 2 8.(a) 4 x 10 6 N (b) 1.6 x 10 7 N (c) 2 x 10 7 N (d) 6.56 x 10 6 N 9.(a) m/s 2 (b) 2.6 m/s 2 (c) 0 m/s 2 (d) 10 m/s 2 (e) 11.5 m/s 2 (f) 8 m/s 2 (b) 1.5 m/s 2 (c) no; thrust is less than weight (d) 5 m/s 2 (e) 6 m/s 2 (f) 5.58 x 10 7 N Cosmology 1 1. A star and all the objects planets and moons - that orbit round it. The objects are held in orbit by the gravitational field of the star. 2. satellite 3. Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune 4. Jupiter 5. Mercury and Venus 6. The inner planets are rocky, the outer planets are gas giants. 7. Dwarf planet 8. Hydrogen and helium gas 9. A system of millions or billions of stars, together with gas and dust particles held together by the gravitational field of the star. 10. The Milky Way 11. The light year 12. Proxima Centauri 4.2 light years away 13. Big Bang 14. Everything that exists all matter and space as a whole. GMV Science. Photocopiable only by the purchasing institution 42

43 Numerical Answers to Questions 15. Any one from (a)the universe is expanding - have liquid water on it - have air with oxygen in it (b) Cosmic microwave (in sufficient quantities) background radiation is detected all around us. (c) There is a lot of hydrogen and helium around in the universe 16. Around 14 billion years 17. Any three from - be rocky (not a gas giant) 18. Exoplanet 19. Goldilocks zone. 20. Using a telescope, manned space missions and unmanned probes and spaceships - not too hot or too cold Cosmology 2 Down 1. and 2. proxima 3. sun 4. telescope 5. colours 7. earth 8. gravity 10. objective 14. mass 15. red 16. all Across 2. prism 4. tiny 6. one 8. galaxy 9. ever 11. orbits 12. space 13. ET 17. white 18.solar system Distances in Space x m x m light years years s x km light years 8. 7 x s ( 2.2million years) x 10 8 km s GMV Science. Photocopiable only by the purchasing institution 43

44 Numerical Answers to Questions Distances in Space 2 1. a) 3 x 10 8 m b) 1.8 x m c) 1.08 x m d) x m e) x m x m s (8.33 minutes) s s light years light years x km Space Exploration 1. Any thing suitable scratch resistant lens coatings, Memory foam mattress etc. 2. a) Satellites b) Nuclear waste will be radioactive for a long time if something happened to a rocket carrying it to the moon that could have catastrophic consequences for us. Storing waste on the moon would need a lot of fuel to get it there and would be storing a potential problem for people in the future. 3. a) The greater the height above Earth, the longer the period of rotation. b) You can track fronts, hurricanes and measure temperature to help forecast weather c) Icecaps, deserts and rainforests can be monitored to see what changes occur annually. d) GPS Global Positioning System. A space based satellite navigation system. Can pinpoint your position with a great deal of accuracy. Now found in cameras and phones as well as sat-nav. e) A geostationary satellite appears to stay in the same place above the earth at all times. It orbits the earth at a height which gives it a period of 24 hours. f) (i) Vehicles can be tracked for security (bank vans). (ii) Animals can be tracked to monitor migration patterns and to check the location of animals which may be under threat from poachers. GMV Science. Photocopiable only by the purchasing institution 44

45 Space Travel Numerical Answers to Questions 1. There are no unbalanced forces acting on the spacecraft. 2. Booster rockets fuel is carried on board the spacecraft. 3. (a) 2.24 x 10 7 s (259.4 days) (b) s (c) (i) Sickness, muscle atrophy, deterioration of the skeleton, puffiness of the face and eyesight problems. (ii) As well as the physical problems there are concerns about how people would cope with being confined to a small space with only a few other people for a very long time. Looking after medical problems could also be difficult. Supplying enough food and drink, especially fresh foodstuffs is another challenge. (d) Mars ; Mars ; Pathfinder 1997; Beagle ; Spirit 2004; Opportunity 2004; Curiosity s s Re-Entry x 10 7 J x (a) 6.4 x J (b) 6.4x J 4.(a) 2.4 x 10 8 J (b) o C 5.(a) 8.75 x 10 8 J (b) 39,062.5 o C 6.(a) 1.25 x J (b) 1.25 x J 6.(c) 35,714 J/kgºC 7 (a) 4.8 x J (b) 4.8 x J (c) 13,333 ºC 8.(a) 61,660.5 J (b) 61,660.5 J 9.(a) 1.2 x J (b) 1.2 x J (c) 3 x 106 N 10.(a) 8.1 x 10 9 J (b) 8.1 x 10 9 J (c) 2025 m GMV Science. Photocopiable only by the purchasing institution 45

46 Numerical Answers to Questions Re-Entry 2 1. (a) A shock wave builds up in front of the spacecraft as it re-enters the atmosphere. The high pressure causes the air to heat up to very high temperatures. (b) The kinetic energy is converted to heat energy. (c) The underside of the shuttle gets hotter than the upper side, so it needs thicker tiles. 2. The meteor is likely to break up into smaller pieces which burn up as the heat energy destroys the meteor. Re-Entry 3 1. (a) Kinetic energy is converted to heat energy. (b) When meteorites enter the atmosphere they heat up and turn into burning vapour the trails of burning gas are visible from Earth. (Shooting stars) 2. Human beings can only stand temperatures within a narrow range. Temperatures in space travel range from well below zero in space, to extremely high temperatures on re-entry. Thermal protection systems protect the astronauts. Ceramic tiles are used on the surface of the space shuttle. 3. (a) Early space programmes had a heat shield which was designed to melt as the spacecraft entered the atmosphere. (b) Space shuttles had a covering of ceramic tiles which are designed to dissipate the heat caused by re-entry. 4. (a) ºC (b) The small sections of aluminium would heat up and vaporise, so nothing would reach the Earth s surface. 5 (a) 5.6 X 10 8 J (b) C (c) Heat is lost to the surroundings. GMV Science. Photocopiable only by the purchasing institution 46

47 Numerical Answers to Questions Projectiles 1 1. (a) Horizontal motion is constant (b) Vertical motion is affected by acceleration due to gravity. (c) That no air resistance is taken into account. 2. (a) Initial vertical velocity 0m/s Final vertical velocity 20m/s Area under velocity time graph = vertical height = 20m (b) The Osprey will be directly above the fish when it hits the water. Projectiles 2 1.(a) 40 m (b) 20 m/s (c) 20 m 2.(a) m (b) 120 m/s (c) 720 m 3.(a) 300 m (b) 100 m/s 4.(a) 8 x 10 7 m (b) m/s (c) m 5.(a) 0.5 s (b) 5 m/s (c) 1.25 m 6.(a) 0 m/s (b) 100 m/s 7.(a) 0 m/s (b) 12.5 s 8.h.dist.=1200m v.dist=1350m 9.(a) 200 m (b) 0.75 m/s 2 (c) 150 m 10.(a) 84 m (b) 24 m/s (c) 28.8 m Projectiles 3 1. a) 8m/s b) 30 m/s c) 1200m d) Aircraft will be directly 2. a) 12 m b) 20 m/s 3. a) 1200m above the bomb when it hits the ground if the pilot does not change the speed or direction of the plane. b) 80 m/s GMV Science. Photocopiable only by the purchasing institution 47

48 Velocity (m/s) Velocity (m/s) Numerical Answers to Questions 4 a) Time (s) b) c) Horizontal distance = 75m, Vertical distance = 125m 5. a) As the arrow drops the target drops at the same rate as they are both affected by the acceleration due to gravity. b) If the wind is blowing the arrow will not fall exactly as expected Time (s) Satellites 1. Microwave ,000,000 m/s 3. They are reflected back down to Earth or absorbed by the Earth s atmosphere. 4. Equator/same/once/orbits/lower Type of Satellite Approximate Height Time taken Notes above the earth (km) for 1 orbit International Space Station 390km 90 minutes Zero gravity Lab Polar Orbit 1000km 100 minutes Monitoring Land use, Weather GPS Fleet 20,000km 12 hours Navigation aid Worldwide Geostationary hours communication Broadcasting TV The Moon 380,000km 28 days Gives us the Earths tides. 5. Curved or parabolic 6. They collect the radiation and bring the radiation to a focus, concentrating the energy over a small area. GMV Science. Photocopiable only by the purchasing institution 48