2.  Julia and Alano are passengers on a train traveling at 5.7 meters per second (m/s) relative to the ground. Julia is sitting facing Alano, with her back to the front of the train. Julia throws a ball to Alano while the train is passing by a platform at a train station. To a person standing on the train station platform, the speed of the ball is traveling at an average speed of 2.2 m/s in the same direction as the train. Relative to the train, what speed is the ball is being thrown?  a. 7.9 meters per second  b. 4.4 meters per second  c. 11.4 meters per second  d. 3.5 meters per second

3.  D. 3.5 m/s

4.  When you are bouncing on a trampoline, why don’t you notice the effects of the gravitational attraction between yourself and the Sun?  a. You are much closer to the Earth than you are to the Sun.  b. The Sun has a very small mass.  c. The Sun is not composed of matter.  d. The Sun has no gravitational attraction for objects on Earth.

5.  A. You are much closer to the Earth than you are to the Sun

6. . If a light bulb with a resistance of 40 ohms is placed in a circuit with a 9-volt battery, what is the current flowing through the bulb?.

7. .225 amps

8.  Bob works with a friend to move his belongings into a new home. They pick up a sofa with a weight of 330.5 Newtons and move it 14.7 meters into another room. How much work, in joules, have Bob and his friend done?

9.  4858 J

10.  The acceleration of gravity on Earth is 9.8 meters per second 2. How much gravitational potential energy, in joules, does a 9.5 kilogram object have when it is positioned at a height of 15 meters?

11.  1397 J

12.  A force can exist between two objects without those objects being in contact. What force is at work when the planet Venus revolves about the Sun?  a. magnetic force  b. electrical force  c. gravitational force  d. effort force

13.  c – gravitational force

14.  How would the gravitational force change if the mass of object one (mass1) increased?  a. The force would decrease.  b. The force would increase.  c. The force would not change.  d. The force would fluctuate randomly.

15.  B - the force would increase

16.  How would the gravitational force change if the objects moved closer together?  a. The force would not change.  b. The force would decrease.  c. The force would fluctuate randomly.  d. The force would increase.

17.  D- Force would increase

18.  Both the Sun and the Moon exert a gravitational force on the water covering the Earth. High and low tides are caused by gravitational forces. Along most coastlines, there are two low tides and two high tides during each 24-hour period. Why is the Moon’s gravitational pull more important than that of the Sun’s in affecting tides?  a. The Moon is a solid object, while the Sun is composed of gases.  b. The Moon is much more massive than the Sun.  c. The Moon is much closer to Earth than the Sun.  d. The Sun is too far away and too small to have any attraction for the Earth’s oceans.

19.  C- The moon is much closer to the earth than the sun

20.  Melissa is driving a boat north on a canal at a water speed of 9.6 meters per second (m/s). The canal water is flowing south at 5.8 m/s. What is the speed of the boat relative to the ground?  A. 19.2 meters per second  b. 15.4 meters per second  c. 3.8 meters per second  d. 11.6 meters per second

21.  C – 3.8 m/s

22.  Compare the gravitational attraction between the objects in A and B below. The mass of all four objects shown is the same.  a. The gravitational attraction between the two objects is greater in A.  b. The gravitational attraction between the two objects is greater in B.  c. As gravity is based solely on mass, the attraction between objects in A and B is the same.  d. The gravitational attraction between the two objects changes at random in both A and B.

23.  A – The gravitational attraction between the two objects is greater in A

24.  The gravitational force between objects depends upon several factors. How would the gravitational attraction between two objects change if the mass of one of the objects decreased?  a. The gravitational attraction would not change.  b. The gravitational attraction would decrease.  c. The gravitational attraction would increase.  d. The gravitational attraction would increase at first, then decrease.

25.  B- the gravitational attraction would decrease

26. At what point(s) is the swing’s gravitational potential energy the greatest? a. A and Bb. B c. A and Cd. A

27.  C- both A and C

28.  How does the swing’s gravitational potential energy change from point A to point B?  a. The gravitational potential energy decreases, then increases between these two points.  b. The gravitational potential energy increases between these two points.  c. The gravitational potential energy does not change between these two points.  d. The gravitational potential energy decreases between these two points.

29.  D- The gravitational potential energy decreases between these two points

30. How does the swing’s kinetic energy change from point A to point B?  a. The kinetic energy does not change between these two points.  b. The kinetic energy increases between these two points.  c. The kinetic energy decreases between these two points.  d. The kinetic energy increases, then decreases between these two points.

31.  B- The kinetic energy increases between these two points

32.  Which statement is true ?  a. An object’s mass has no effect on its potential energy.  b. Potential energy is converted to kinetic energy as a stationary object begins to move.  c. Kinetic energy is converted to potential energy as a stationary object begins to move.  d. A stretched rubber band stores no energy.

33.  B- Potential Energy is converted to kinetic as a stationary object begins to move.

34.  The chart shows how the weight of objects which weigh 75 pounds and 2000 pounds on Earth would differ on various solar system bodies. How much stronger would the gravitational attraction be for an object on Earth than it would be on Venus?  A. 2.6 times strongerB. 2.8 times stronger  C.6.0 times strongerD.1.1 times stronger

35.  D- 1.1 times

36.  Power is defined as the rate at which work is done. It is calculated by dividing work, in joules, by time, in seconds. Power is expressed in units of watts, where 1 watt equals 1 joule per second. How much power, in watts, is required for a weight lifter to lift a weight of 1307.5 Newtons to a height of 1.4 meters in a 3.9-second period?

37.  469 watts

38.  In picture (a), the helicopter is flying east at 34.5 meters per second (m/s) relative to the ground. The train is moving east at 8.3 m/s. If the motorcycle is moving east at 6.7 m/s relative to the train, what is the speed of the helicopter relative to the motorcycle in meters per second?

39.  19.5 m/s

40.  Electrical power refers to the rate at which electrical energy is converted into another form of energy. Electrical power can be calculated by multiplying current, in amperes, by voltage, in volts. A lamp has a current of 0.7 amperes flowing through it and a potential difference of 120 volts. How much power, in watts, does the lamp use?

41.  84 watts

42.  Why don’t you notice the effects of the gravitational attraction between yourself and a pencil you are holding?  a. Your mass is much greater than the pencil’s mass.  b. The pencil has no mass.  c. Both you and the pencil have a tiny mass compared to Earth’s mass.  d. You are too far away from the pencil.

43.  C- Both you and the pencil have a tiny mass compared to the Earth’s mass

44.  How does the swing’s kinetic energy change from point B to point C?  a. The kinetic energy does not change between these two points.  b. The kinetic energy decreases between these two points.  c. The kinetic energy decreases, then increases between these two points.  d. The kinetic energy increases between these two points.

45.  The kinetic energy decreases between these two points

46.  Erin heats water (H 2 O) to a temperature of 85°C. She leaves the beaker on the counter until the water temperature falls to 24°C, then places the beaker in a freezer until the water temperature falls to 10°C.  When the water temperature falls to 10 degrees Celsius from 24 degrees Celsius, the water molecules ____.  a. move more slowly  b. initially move more slowly, but then move faster  c. do not change their speed  d. move faster

47.  A= move more slowly

48.  What is meant by the efficiency of a machine?  a. It measures the rate at which work is done.  b. It measures the number of times a machine multiplies the effort force applied to it.  c. It measures how much work is put into a machine.  d. It measures how much work put into a machine is changed to useful output work.

49.  D- it measures how much work put into a machine is changed to a useful output work

50.  Why don’t you notice the effects of the gravitational attraction between yourself and the planet Jupiter?  a. There is no gravitational attraction between gaseous objects and solid objects.  b. Jupiter is composed of gas, and therefore has no mass.  c. Your mass is much greater than Jupiter’s mass.  d. Your mass is small and Jupiter’s distance from you is great.

51.  D- Your mass is small and Jupiter’s distance from you is great