Wheeler High School 2008 GHSGT Science Review Physics Module I Overview, Motion, Forces Energy

1. Wheeler High School 2008 GHSGT Science Review � Physics � Module IOverview, Motion, Forces & Energy

2. Forces & Motion Understand the relationship between force, mass, and motion. Calculate velocity and acceleration Apply Newton�s First Law of Motion, the law of inertia. Relate falling objects to the force of gravity Understand the difference between mass and weight. Calculate work and mechanical advantage

3. Waves Describe the properties of waves Understand that all waves transfer energy Associate frequency and wavelength with the energy transferred by electromagnetic and mechanical waves. Understand the concepts and can identify examples of reflection, refraction, interference, and diffraction. Analyze the effects of different mediums on the speed of sound.

4. Electricity Understand the properties of electricity and magnetism Describe magnetism and electrical charges in the context of electricity, magnetism, electromagnets, and simple motors.

5. Vocabulary

6. Motion One possible unit of speed is ___. a. miles per hour b. kilometers per hour c. light years per century d. all of the above e. none of the above

7. The answer is D. Average Speed is a distance traveled divided by the time required for the trip. a. speed = distance / time b. velocity = distance / time in a direction c. mi/hr, km/hr, and m/s are common units for speed or velocity.

8. Motion Acceleration is defined as the change in ___. a. distance divided by the time interval b. velocity divided by the time interval c. time it takes to move from one speed to another speed d. time it takes to move from one place to another place e. velocity of an object

9. The answer is B. Acceleration is the change in velocity divided by the time it took to change the velocity. a. acceleration = ? velocity / ? time b. The units for acceleration are a distance over a time squared (i. e. m/s2).

10. Motion Suppose you take a trip that covers 240 km in 4 hours. Your average speed is ___. a. 960 km/hr b. 480 km/hr c. 240 km/hr d. 120 km/hr e. 60 km/hr

11. The answer is E. Speed = distance / time Speed = 240 km / 4 hr Speed = 60 km/hr

12. Newton�s Laws A sheet of paper can be withdrawn from under a carton of milk without toppling it if the paper is pulled quickly. The reason this can be done is that ___. a. The milk carton has very little weight. b. There is an action/reaction pair operating. c. Gravity pulls very hard on the milk carton. d. The milk carton has inertia. e. none of the above

13. The answer is D. Newton�s first law states that an object tends to retain its current state of motion unless acted on by a net force. This is the law of inertia. a. Objects with more mass (i.e. milk carton) have more inertia and resist changes in motion.

14. Newton�s Laws Compared to its weight on the earth, a 10 kg object on the moon will weigh ___. a. less b. more c. the same amount

15. The answer is A. Weight is the force that an object experiences due to gravity. An object�s weight changes depending upon where it is (i. e. on the earth, on the moon, or on Mars). a. The units for any force are Newtons. Mass is the amount of stuff in an object. An object�s mass never changes no matter where its located. a. Mass is measured in kilograms.

16. Newton�s Laws Newton�s second law states that force is proportional to both mass and acceleration (F = m a). a. The acceleration due to gravity on the moon is less than that on earth, therefore the object will have a smaller weight. b. mass and weight are often confused. An object will have the same mass (amount of stuff) on both the earth and the moon.

17. Newton�s Laws Newton�s third law states that, for every action, there is an equal and opposite reaction. a. Forces always act in pairs. For example, if you kick a football, your foot applies a force to the football. However, the football applies an equal and opposite force to your foot.

18. Newton�s Laws Friction ___. a. acts in a direction that opposes the motion of an object. b. comes from interactions between the surface of an object and it�s surroundings c. is the name given to the force acting between surfaces sliding between one another. d. all of the above e. none of the above

19. The answer is D. Friction is the force that exists between contacting objects moving past one another. a. Friction on an object is always opposite the direction of the object�s motion. b. The units for friction, as for any force, are Newtons.

20. Momentum Which has more momentum, a large truck moving at 30 miles per hour or a small truck moving at 30 miles per hour? a. the large truck b. the small truck c. Both trucks have the same momentum.

21. The answer is A. The momentum of an object is the product of an object�s mass and velocity. a. Momentum (p) = (mass) (velocity) b. The units of momentum are kg m/s. c. Since the trucks have the same velocity, the one with the larger mass has the larger momentum.

22. Momentum A 4 kg ball has a momentum of 12 kg m/s. What is the ball�s speed? a. 3 m/s b. 4 m/s c. 12 m/s d. 48 m/s e. none of the above

23. The answer is A. p = (m) (v) v = p / m v = 12 kg m/s / 4 kg v = 3 m/s

24. Work If Harry pushes an object with twice the force for twice the distance, he does ___. a. the same work b. twice the work c. four times the work d. eight times the work

25. The answer is C. Work is the force times the distance over which the force acts. a. Work= (force) (distance) b. The units for work are Joules. b. Since there was 2 times as much force and 2 times as much distance. c. W = (2F) (2d) d. W = 4 (F) (d) e. The amount of work he did increased by a factor of 4.

26. Power If Lydia pushes a red box that weighs 10 N for 5 m across a room in 10 seconds, and she pushes a blue box that weighs 10 N for 5 m across the same room in 5 seconds, with which box did she use more power? a. the red box b. the blue box c. She expended the same amount of power for both boxes.

27. The answer is B Power is the work applied divided by the amount of time it took to perform the work. a. The units for power are Watts. b. Power = work / time c. Power = (10 N) (5 m) / 5 s Power = 10 Watts for the blue box d. Power = (10 N) (5 m) / 10 s Power = 5 Watts for the red box

28. Energy As a pendulum swings back and forth ___. a. Potential energy is transformed into kinetic energy. b. Kinetic energy is transformed into potential energy. c. At the lowest part of the swing, its energy is all kinetic. d. At the end points of the swing, its energy is all potential. e. all of the above

29. The Answer is E Kinetic energy is energy of motion. Potential energy is stored energy or energy of position. a. The pendulum is at rest at the top of its swing. It has no kinetic energy, but much gravitational potential energy. b. The units for work, kinetic energy and potential energy are Joules.