National 5 Dynamics and Space Self Checks 1.1 Kinematics Speed, Distance and Time 1. A runner completes a 200 m race in 25 s. What is his average speed? 2. An athlete takes 4 minutes 20 s to complete a 1500 m race. What is the average speed? 3. A fighter jet can travel at 680 m/s. How far will it travel in 25 s at this speed? 4. A girl can walk at an average speed of 2 m/s. How far will she walk in 20 minutes? 5. How long will it take a cyclist to travel 40 km at an average speed of 5m/s? 6. On a fun run, a competitor runs 10 km in 1 hour 3 minutes. What is her average speed in: km/h? m/s? 7. Look at this timetable for a train between Glasgow and Edinburgh: Station Time Distance from Glasgow Glasgow 0800 0 km Falkirk 0820 34 km Linthligow 0828 46 km Edinburgh 0850 73 km What was the average speed for the whole journey in m/s? What was the average speed in m/s between Glasgow and Falkirk? 1
8. A trolley with a 10 cm card attached to it is released from A and runs down the slope., passing through a light gate at B, and stopping at C. A The time from A to B = 0.8 s Time on light gate timer = 0.067 s C B 60 cm 40 cm What is the average speed between A and B? What is the instantaneous speed at B? Vectors and Scalars 9. What is the difference between a vector quantity and a scalar quantity? 10. A man walks from X to Y along a winding road. N Y 2 km X Road = 3.6 km What is his displacement at the end of his walk? What distance has he walked? 11. If the walker in question 10 took 40 minutes to complete his walk. Calculate: His average speed. His average velocity. 12. One complete lap of a running track is 400 m. An athlete completes one lap in 48 s. What is his: distance travelled? displacement? average speed? 1 lap = 400 m (d) average velocity 2
13. A car travels 40 km north, then turns back south for 10 km. The journey takes 1 hour. Find: (d) The displacement of the car. The distance the car has travelled. The average velocity of the car. The average speed of the car. 14. A motorcyclist drives 60 km north, then 80 km east, as shown in the diagram. The journey takes 2 hours. Calculate: The total distance travelled. 80 km (d) The displacement. The average speed. The average velocity. 60 km 15. A walker travels 2 km south, then 5 km east, as shown in the diagram. The journey takes 1 hour 15 minutes. Calculate: The displacement. The average velocity of the walker. 5 km 2 km Acceleration & Velocity-Time Graphs 16. A football moves with an acceleration of 3 m/s 2. Explain what this means. 17. A jaguar can reach 27 m/s from rest in 9.0 s. What is its acceleration? 18. A space shuttle reaches 1000 m/s, 45 s after launch. What is its acceleration? 19. A bullet travelling at 240 m/s hits a wall and stops in 0.2s. What is its acceleration? 20. A bowling ball is accelerated from rest at 3m/s 2 for 1.2s. What final speed will it reach? 21. How long will it take a car to increase its speed from 8m/s to 20 m/s if it accelerates at 3m/s 2? 3
22. The graph below shows how the velocity of a car varies over a 40 s period. 15 velocity (m/s) 0 10 20 30 40 time (s) Describe the motion of the car during this 40 s period. Calculate the acceleration of the vehicle. How far does the car travel while accelerating? 23. Use the graph below to answer the following questions. velocity (m/s) 30 0 30 60 90 105 time (s) During which time is the vehicle at a constant acceleration? Calculate the values of: (i) (ii) The initial acceleration. The final acceleration. (d) (e) What is the breaking distance of the car? What is the total distance travelled? What is the average velocity of the car? 24. A police reports details the motion of a car as follows: A car accelerates from rest at 2m/s 2 for 8 s, then travels at a constant velocity for 12 s, finally slowing steadily to a halt in 4 s. Draw a velocity-time graph to show the motion of the car. 4
25. The graph below describes the motion of a cyclist. 8 6 velocity (m/s) 0 20 40 60 75 time (s) What is the value of the maximum positive acceleration? Show by calculation whether the cyclist travels further whilst accelerating, or whilst cycling at the maximum velocity. 26. The velocity-time for a high speed train is shown below. 27 velocity (m/s) 9 0 2 6 12 time (s) Due to engineering works on an upcoming bridge 200 m away, the train has to slow down to 9 m/s. The driver applies the brakes 2 s after seeing the warning sign. the driver applies the brakes. Is the train travelling at the correct speed when it reaches the bridge. Justify your answer with a calculation. 5
1.2 Dynamics Gravity, Mass and Weight Use the following table to answer the following questions: 27. What is the weight of a 10 kg bag of potatoes? 28. What is the weight of a 250 g bag of sweets? 29. What is the mass of a 450 N girl? 30. What is the weight of a 10,000 kg spacecraft on: Earth Mars Venus? 31. What would a 60 kg man weigh on Jupiter? Planet g (N/kg) Mercury 3.7 Venus 8.8 Earth 9.8 Mars 3.8 Jupiter 26.4 Saturn 11.5 Uranus 11.7 Neptune 11.8 Pluto 4.2 32. An astronaut who weighs 784 N on Earth goes to a planet where he weighs 304 N. Calculate the mass of the astronaut. Show by calculation which planet the astronaut is on. 33. What would an astronaut weigh on Earth, if his weight on Venus was 528 N? Newton s First Law 34. The diagram below shows the forces acting on a cyclist moving at a constant velocity. Friction 1200 N What can you say about the unbalanced force acting on a cyclist? How big is the friction force? 6
35. The diagram below shows the forces acting on a sky diver. Air resistance Mass = 70 kg Weight The sky diver is falling at a constant velocity. State the name given to this velocity. Calculate the weight of the sky diver. State the size of the air resistance force? 36. Explain, using Newton s First Law, why passengers without seat belts in a moving car are thrown forwards in the car, when the car stops suddenly. Newton s Second Law 37. What force is needed to accelerate a 5 kg mass at 3m/s 2? 38. What force will accelerate a 250 g mass at 2m/s 2? 39. What force would be needed to accelerate a 10 000 kg lorry at 1.5 m/s 2? 40. What mass would accelerate at 2 m/s 2 when acted upon by a 12 N force? 41. An aircraft is flying at a constant height. The mass of the aircraft and its passengers is 50 000 kg. 12000 N 44000 N Find the unbalanced force acting on the aircraft. Find the acceleration of the aircraft. 7
42. The forces acting on a sprinter are shown below: 45N 150N Find the resultant force acting on the athlete. Find the mass of the athlete if she is accelerating at 1.5 m/s 2. 43. A tug boat is sailing along a river with an engine force of 3x10 3 N. It experiences a tidal force of 2.1x10 3 N as shown in the diagram below. 3 x 10 3 N 2.1 x 10 3 N Find the resultant force acting on the boat. Find the acceleration of the boat if it has a mass of 15 000 kg. 44. A cheetah can accelerate at 2.96 m/s 2. They have an average mass of 70 kg. Find the unbalanced force acting on the cheetah. If the cheetah is providing a forward force of 1000N, find the force of friction acting on the cheetah. 45. An 800 kg car is accelerated from 0 to 18 m/s in 12 seconds. What is the resultant force acting on the car? At the end of the 12 s period the brakes are operated and the car comes to rest in a time of 5 s. What is the average braking force acting on the car? 46. A rocket of mass 8500 kg accelerated at 15 m/s 2 during take off. Find the unbalanced force acting on the rocket. Find the thrust given to the rocket from the engines. 8
47. During a paper airplane contest a pupil throws a plane with a force of 15N. There is a side breeze of 7 N as shown below: 7 N 15 N Find the resultant force acting on the paper airplane. If the plane has a mass of 35g find the acceleration of the plane. Calculate the weight of the plane. (d) State the up thrust required to glide the plane at a constant height. 48. While in space a rocket of mass 9000 kg is travelling at a constant speed. What is the unbalanced force acting on the rocket? The rocket fires a booster, explain why this is only fired for a short time. 49. When landing, the rocket in Q48 uses a parachute which creates a drag force of 7000 N. Find the acceleration of the rocket during the descent. Draw a diagram to show the forces acting on the rocket. Work (E w = Fd) 50. A man pushes an empty wheelbarrow for 60 m using a 50 N force. How much work has he done in moving the wheelbarrow? 51. Once filled, the man applies a force of 100 N to the wheelbarrow but fails to move it. How much work has he done? 52. A train exerts a force of 10 000 N to pull a carriage a distance of 400 m. How much work is done? 53. A gardener does 1200 J pushing a lawnmower with a force of 100 N. How far did she push the lawnmower? 54. A man uses up 1000 J by pulling a heavy load for 20 m. What force did he use? 55. A man weighing 600 N climbs stairs in an office block which are 40 m high. How much work does he do? 56. A worker pushes a 4 kg crate along the ground for 3 m using a force of 20 N, then lifts the crate up to a ledge 1 m high. How much work does he do altogether? 9
Newton s Third Law 57. State Newton s Third Law. 58. Identify the Newton pairs in the following situations. Kicking a football Hitting a baseball (d) Space Shuttle take off Pushing in a drawing pin Freefall and Terminal Velocity 59. Explain how astronauts in orbit appear to be weightless 60. What is the acceleration due to gravity on Earth? 61. Explain why a hammer and a feather would hit the ground at the same time if they were both dropped from the same height in a vacuum. Assume the experiment is carried out on Earth. 62. What speed would a 500g hammer hit the ground if it took 3s to fall? 63. An object is thrown upwards with a speed of 20 m/s. How long does it take to reach the top of it s flight? 64. Describe the motion of a sky diver as she falls through the air including the section were the parachute opens. Your answer should include a velocity - time graph. Projectiles 65. Draw a graph for the horizontal component of velocity against time for a projectile. 66. Draw a graph for the vertical component of velocity against time for a projectile. 10
67. A stone thrown horizontally from a cliff lands 24 m out from the cliff after 3 s. Explain the shape of the path followed by the stone. Calculate the horizontal speed of the stone. Calculate the vertical speed at impact. 68. A ball is thrown horizontally from a high window at 6 m/s and reaches the ground after 2 s. Calculate: The horizontal distance travelled. The vertical speed at impact. 69. An aircraft flying horizontally at 150 m/s, drops a parcel which hits the target after 8 s. Find: (d) The horizontal distance travelled by the parcel. The vertical speed of the parcel at impact. The distance travelled horizontally by the aircraft as the parcel fell. The position of the aircraft relative to the parcel at impact. 70. 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, horizontal velocity against time. vertical velocity against time. from the graphs calculate the horizontal and vertical distances travelled. 71. 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. The arrow takes 3 s to hit the target. 12 m/s A Calculate the distance between the target and archer. B Find the height of the target if the arrow has a final vertical velocity of 2 m/s 11
1.3 Space Distances in Space 72. What is meant by the term light year? 73. Convert the following distances from light years into metres: Earth to nearest star: 4.2 light years. Earth to centre of galaxy: 26 000 light years. 74. Convert the following from metres into light years. Earth to the Sun: 1.5x10 17 m. Earth to Andromeda Galaxy: 1.9x10 19 m. 75. It takes 9 years for the light from Sirius to reach us on the Earth. How far is Sirius in metres? How long would it take to reach Sirius travelling at 1200 ms -1? 76. The nearest Galaxy is 1.9x10 19 m away. How long would it take to travel to the galaxy at the speed of light? How long would it take to travel to the galaxy at 1200 ms -1? 77. What is the name given the to theory that describes the origin of the Universe? What evidence is there to support this theory? 78. How old is the Universe in years? Understanding the Universe 79. Different telescopes are used for different purposes. Give the names of two different types of telescopes. 80. Draw and label a diagram for a refracting telescope. 81. Which lens is used to alter the brightness of the image seen in a refracting telescope. 82. Refracting telescopes were initially used to view stars and nearby planets. Explain one limitation of using a refracting telescope to view objects further away. 84. The Hubble Space Telescope orbits the Earth and takes picture of far away Galaxies. Explain why the images from the Hubble telescope are very clear. 85. Using large telescopes, scientists have discovered evidence of The Big Bang. Explain what this evidence is? 12
86. Explain why Earth is suitable for sustaining life. 87. Describe what is meant by an Exoplanet. 88. Why can we not detect an Exoplanet using a telescope? 89. Describe how Exoplanets are detected. 90. Scientists searching for Exoplanets use the Astronomical Unit. 1 A.U. is the distance from the Sun to Earth (the Habitable Zone ) The Habitable Zone is the name given to the region in which a planet is thought to be able to sustain life. A particular star is twice as bright as our Sun: Estimate the Habitable Zone for this particular star. Give a reason for your answer. 91. Explain why it is important for humans to have a better understanding of the Universe. Space Travel 92. The Space Laboratory Curiosity was designed to carry out experiments on Mars. Why is it not suitable to send humans to Mars to carry out these experiments. 93. The International Space Station orbits the Earth and carries out research in low gravity. Why might this be useful? 94. Various technologies have been designed for space programs throughout the years. Give two examples of technologies which are now used in our everyday lives. 95. As well as the benefits mentioned in earlier questions, space travel and exploration also have disadvantages. From the list below select two categories and describe how these could be classed as a disadvantage. Political Issues Accidents Health Finance 96. Explain what the potential problems are for a space shuttle on re-entering the Earth s atmosphere. Give two solutions that are adopted to overcome these potential problems. 97. A heat shield on a spacecraft has a mass of 70 kg. The spacecraft is travelling at 900 m/s. On re-entry into the Earth s atmosphere, the velocity of the spacecraft is reduced to 250 m/s. Calculate the change in kinetic energy of the heat shield. 13
98. The heat shield in question 97 has a specific heat capacity of 980 J/kg o C. Calculate the change in temperature of the heat shield. 99. What causes the change in temperature calculated in question 98? Using the Spectrum 100. List in order of increasing wavelength, the members of the electromagnetic spectrum. 101. What property do all of the members of the electromagnetic spectrum have in common? 102. Describe one use for radio waves in the space industry. 103. White light can be split up into different colours. X Y Z Name the colours present at points X,Y and Z. Explain why the colours of white light can be split this way. 104. Yellow light is part of the visible spectrum. The wavelength of yellow light is 5.9x10-7 m. The visible spectrum also contains red, blue and green light. Use your knowledge of the light spectrum to copy and complete the table below. Colour Wavelength (m) 7 x 10-7 Yellow 5.5 x 10-7 4.5 x 10-7 14
105. Use the table in question 105 to find the frequency of: Blue light Red light 106. The line spectrum of distant stars can be used to identify elements which are present in that star. Explain how this is the case. 107. Explain how the line spectrum of the Sun was used to discover the element Helium. 108. Some spectral lines of radiation from a distance star are shown below: Spectral lines of radiation from distant star The spectral lines of a number of elements are also shown. Cadmium Calcium Krypton Mercury Use the spectral lines of the elements shown above to identify which of these elements are present in the distant star. 109. The following elements were discovered to be on Titan: Helium Using the line spectra of each individual element, sketch what the line spectra from Titan may have looked like. Hydrogen Mercury Nitrogen 15