Provide the units for each of the following quantities shown in the table. Circle all the quantities that are vectors.

Transcription

1 Physics Final Exam Review Units covered Metric conversions/scientific practices/accuracy vs Precision Vectors/Kinematics (1D & 2D motion, circular motion) Momentum & Impulse Forces Energy Electricity & Magnetism Waves Light Provide the units for each of the following quantities shown in the table. Circle all the quantities that are vectors. Quantity Unit Related Equations Displacement Average Velocity Acceleration Force Momentum Kinetic Energy Potential Energy Work Power Current Impulse Wavelength 1

2 Unit 1: Metric conversions/scientific practices/accuracy vs Precision Define the following terms: Hypothesis: Scientific law: Scientific theory: Precision: Accuracy: Independent variable: Dependent variable: Answer/solve completely. 1. Identify if the following are accurate, precise, both or neither. 2. Given the following measurements for the length of an object. Are the measurements precise/accurate or neither, if the true value is 18.2 cm? Why? 18.1 cm 19.2 cm 18.3 cm 3. How many significant digits are in the following? a c b d Add the following numbers and report your answer to the correct number of significant digits. a b Multiply or divide the following numbers and report your answer to the correct number of significant digits. a. 8 x 5.02 c. 900 / 56 b. 10 x 4 6. Convert the following. a cm = m d mm = m b. 5.0 ks = s e. 50 cm/s = m/s c. 6.5 m/min = m/s f. 87 dm/min = m/s 7. Expand the following numbers from scientific notation. a x 10-4 b x

3 Vectors/Kinematics 1. What is the difference between a vector and a scalar? Give two examples of each. 2. A girl leaves a history classroom and walks 10 meters north to a drinking fountain. Then she turns and walks 30 meters south to an art classroom. a. What is the girl s total displacement (with direction)? b. What is the girl s total distance traveled? 3. Resolve the following vectors (draw them and find the resultant vector) a. 10 m North, 13 m East b. 8.0 km south, 30 km east Equations: sinѳ = cosѳ = adj hyp tanѳ = opp adj a 2 + b 2 = c 2 4. A vector is a quantity that has a. Magnitude and time b. Time and direction c. Magnitude and direction 5. A scalar is a quantity that has only a. Direction b. Magnitude c. Time d. Force Two cyclists A and B are in a race. Answer the following questions. (6-10) 6. Which is moving faster at the start of the race? B A 7. What happens when the lines cross? 8. Which is moving faster at the end of the race? Position (m) 9. Is the velocity of cyclist B increasing, decreasing or staying constant? 10. When do they have the same speed? Time (s) 11. A crab can crawl 24 meters in 6 seconds at constant velocity. How far can the crab crawl in 18 seconds? 3

4 A hungry physics student is heading to lunch at Jimmy John s. For part of the trip they drive their vehicle at a constant speed of 20 m/s for a total of 1000 meters. 12. Draw a position vs. time graph for the motion of the car during the trip. Position Time 13. How much time does it take for the student to drive 1000 meters? The student from earlier on his way to Jimmy John s applies the brakes so that he can pull into a parking spot. 14. What is the total distance of the car as it comes to a stop? 15. What is the acceleration of the car as it comes to a stop? 25 Velocity (m/s) 16. Draw a position vs. time graphs best represents the car s motion Time (s) 17. Draw an acceleration vs. time graphs best represents the car s motion. 4

5 Two-dimensional motion & circular motion Define the following: Projectile: Free fall: Gravity: Trajectory: Circular motion: Centripetal: Inertia: Equations to know: v = v + at d d = v t + at v = v + 2ad t = ( ) F = v = π a = 1. If a rock and a feather are dropped in a vacuum, which one hits the ground first? Why? 2. Suppose an object is in free fall. Each second the object falls a. It s the same distance as in the second before. b. A larger distance than in the second before c. With the same instantaneous speed d. With the same average speed 3. A projectile s velocity at the peak of its trajectory is. 4. If a freely falling object were somehow equipped with a speedometer, its speed reading would increase each second by a. About 5 m/s b. About 10 m/s c. About 15 m/s d. A variable amount 5. In the absence of air resistance, the angle at which a thrown ball will go the farthest is a. 15 degrees b. 30 degrees c. 45 degrees d. 55 degrees 6. The Roadrunner drops a brick from an 80 m cliff. What is the velocity of the brick upon impact with the ground? How long does it take to hit the ground? 5

6 7. Clydell kicks a football at an angle of 35⁰ at a velocity of 12 m/s. What are the horizontal and vertical components of the football s velocity? How long is the football in the air? How far horizontally does the football travel? What is the maximum height that the football reaches? 8. A rock is dropped from a tall building. Neglect the effects of air resistance. a. What is the acceleration of the ball? b. How fast will it be moving after 3 seconds? c. How far will the ball have traveled in 3 seconds? 9. If you increase the radius between two objects, what happens to the force? 10. What causes a person to lean to the right as a car turns sharply to the left? 11. If something is moving in a circle, what direction does the centripetal force point? 12. If you whirl a tin can on the end of a string and the string suddenly breaks, the can will a. Fly directly away from you b. Fly off, tangent to its circular path c. Fly directly toward you d. Spiral in toward your hand 13. A 13 g rubber stopper is attached to a 0.93 m string. The stopper is swung in a horizontal circle making one revolution in 1.18 s. Solve for the following. a. Centripetal acceleration b. Centripetal force 14. A 615 kg racing car completes one lap in 14.3 s around a circular track with a radius of 50.0 m. The car moves at constant speed. a. What is the acceleration of the car? b. What forces is exerted on the tires to produce the acceleration? 6

7 Forces Define the following: Newtons 1 st Law of motion: Newtons 2 nd Law of motion: Newtons 3 rd Law of motion: Force: Net force: Equilibrium: Weight: Normal force: Frictional force: Tension: Equations to Know: F = ma F = W = mg g = What is the difference between a contact force and a field force? Give examples of each. 2. What is a free body diagram? What is it used for? 3. Draw a free body diagram for the following a. A egg falling from a tree b. A book at rest on a table c. Two people pushing off of each other d. A rope lifting a bucket 4. Calculate the weight of the following: a. 5 gram object b. 75 kg object 5. Compared to its mass on Earth, the mass of a 10 kg object on the moon is a. The same b. More c. Less 6. If the force acting on a cart doubles, what happens to the cart s acceleration? 7. A bug splatters against the windshield of a moving car. Compared to the force of the car on the bug, the force of the bug on the car is smaller or larger? Why? 8. A 600 N woman sits on the floor, the floor exerts a force on her of. 9. If a person has a weight of 750 N, what is the mass of the person? 10. A box, with a mass of 10 kg, is pushed with a force of 50 N. What is the acceleration of the box? 11. Your shopping cart has a mass of 65 kilograms. In order to accelerate the shopping cart down an aisle at 0.3 m/sec 2, what force would you need to use or apply to the cart? 12. A 3 kg box is being pulled with a force of 10 Newtons. Between the floor and the box is 15 N of frictional force. Draw and label each force. Is the person pulling the box able to move it? Justify your answer. 7

8 Momentum and Impulse Equations to Know: m v + m v = (m + m )v m v + m v = m v + m v J = m v = Ft p = mv Define: Momentum: Impulse: Elastic collision: Inelastic collision: Law of conservation of momentum: 1. What is the equation for momentum? 2. Can a bullet have the same momentum as a truck? 3. A moving truck has momentum. If it moves twice as fast, its momentum is. 4. Calculate the momentum of a bird that is 0.5 kg and moves at a rate of 20 m/s. 5. What is the difference between an elastic and an inelastic collision? 6. Is momentum a vector or a scalar quantity? Explain why. 7. How do you calculate impulse? 8. What is the change in momentum of a 950 kg car that travels from 40 m/s to 31 m/s? 9. How does a crumple zone help to reduce the force of impact in a car accident? 10. Give two other safety measures used to reduce the impact in a car accident? 11. A football player kicks a ball with a force of 50N. Find the impulse on the ball if his foot stays in contact with the football for 0.01s. 12. A van of mass 1200kg was moving at a velocity of 8m/s when it was involved in a head on collision with a car moving in the opposite direction. Assuming that the van came to stop after the collision, a. calculate the momentum of the van before the collision b. work out the momentum of the van after the collision c. find the change in momentum of the van 13. A 1250 kg car is moving down the highway with a velocity of 32.0 m/s when it bumps into the car ahead of it which has a mass of 875 kg and a velocity of 25.0 m/s. After the collision, the two cars stick together. What will be the resulting velocity of the two cars together? 8

9 Energy Equations to Know: Potential Energy (GPE or PE) = mgh Kinetic Energy (KE) = ½ mv 2 power = Work time Work = FdcosƟ KE i + PE i = KE f + PE f Define the following: Kinetic Energy: Potential Energy: Law of conservation of energy: Work-Energy Theorem: Mechanical Energy: 1. Consider a stopper hanging from a string. The stopper is used as a pendulum. Where in the motion of the pendulum is the potential energy the highest? Kinetic energy? 2. If kinetic energy of a 15kg mass is 175J, what is its speed? 3. What happens to the kinetic energy of an object if the velocity is doubled? 4. Give an example where the object has 100% potential energy. 5. You decide to climb on the roof of your house to take down the Christmas lights that have been there since December. Your mass is about 60 kg. Calculate the potential energy. 6. A box has a mass of 5.8kg. The box is lifted from the garage floor and placed on a shelf. If the box gains 145J of Potential Energy (PE), how high is the shelf? 7. A 75.0 kg man pushes on a 500,000 t wall for 250 s but it does not move. How much work does he do on the wall? 8. For work to be done, force and displacement must be in the direction. 9. Calculate the work done when a 20-N force pushes a cart 3.5 m? 10. A 1.8 kg book has been dropped from the top of the football stadium. Its speed is 4.8 m/s when it is 2.9 meters above the ground. A. What is its total mechanical energy? (mechanical energy includes kinetic, gravitational potential, and elastic potential but not internal forms of energy such as thermal or chemical) B. What was the total mechanical energy of the book at the instant it was released? C. How high is the stadium? 9

10 Nuclear Energy Define the following: Nuclear decay: Atomic Number: Atomic Mass: Isotope: Alpha decay: Beta decay: Nuclear fusion: Nuclear fission: Half life: Gamma decay: Radioactive: Balance the following nuclear decay equations according to the type stated. The following atoms all undergo alpha particle emission. Write the complete nuclear equation. 210 Po U 92 + The following atoms all undergo beta decay. Write the complete nuclear equation. 14 C Sr Pu 4 He + Type: 2 1. What particle do all alpha decay reactions release? 2. What is the difference between nuclear fission and nuclear fusion? 3. Which from question 2 occurs in stars? Nuclear power plants? 4. Isotopes of an element: A) Have the same number of protons and electrons, but a different number of neutrons. B) Have different number of electrons. C) Have different number of protons. D) Have the same number of neutrons and protons, but a different number of electrons. 5. If the half-life of Uranium-232 is 70 years, how many half-lives will it take to for 10 g to be reduced to 1.25 g? 6. After 42 days a 2.0 g sample of phosphorus-32 contains only.25 grams of the isotope. What is the half-life of phosphorus- 32? 7. How many protons, neutrons and electrons are in each of the following? a. Carbon -14 b. Uranium 238 c. Cesium

11 Electricity and Magnetism Equations to Know: I = F = k = 9 x 10 9 N-m 2 /C 2 R eq = R 1 + R 2 + R 3. = Define the following and give the units where applicable: Current: Conventional current: Resistance: Voltage: Circuit: Grounding: Static Electricity: 1. Describe the differences between a series circuit and a parallel circuit. 2. What is the current in a 10V circuit if the resistance is 2Ω? 3. What is the current in a 120V circuit if the resistance 20Ω? 4. What is the current in a 120V circuit if the resistance 10Ω? 5. What is the resistance of a circuit with 120V and 5A? 6. A resistor is connected in series to a 120-V generator and two resistors that are connected in parallel to each other. a. Draw the circuit diagram. b. What is the total resistance of the load? c. What is the magnitude of the circuit current? 8. A is described as a device that converts chemical energy to electric energy. a. battery c. lightbulb b. resistor d. capacitor 9. What device measures the current in a circuit? 10. What is equivalent resistance? Give an example to help explain. 11

12 Waves Equations to Know: Define the following: Wave: Medium: Transverse Wave: Longitudinal wave: Mechanical wave: Amplitude: Wavelength: Period: Standing wave: Node: v = λf Frequency: Resonance: Antinode: Draw a longitudinal wave and label the compression and rarefactions. Draw a transverse wave and label the wavelength, amplitude, crest, trough, and wave height. 1. Give examples of the following: a. Longitudinal wave: b. Transverse wave: 2. Which of the following has the largest wavelength? Radio waves visible light x-rays 3. Which of the following has the largest frequency? Radiation Microwaves Ultraviolet waves 4. Sound travels through air at about 330 ms-1. Calculate the wavelength of the sound of frequency 256 Hz. 5. A sound wave in a steel rail has a frequency of 620 Hz and a wavelength of 10.5 m. What is the speed of sound in steel? 6. What is the frequency of a pendulum that is moving at 30 m/s with a wavelength of 0.35 m? 12