Physics 101 Midterm 1

YOU MUST CIRCLE YOUR ANSWERS ON THIS EXAM AND TURN IT IN WITH YOUR SCANTRON.

Choose the best answer. Use g = 10m/s2 and ignore air resistance and friction unless mentioned.

Use MKS units. Try to answer as many as you can before digging in the book. Good Luck and Have Fun!

1. Mass is a measure of a) speed b) acceleration c) inertia d) weight e) all of these

  1. An object’s resistance to change its state of motion is a) weight b) force c) inertia d) all of these

3. An object's resistance to rotate is a) angular momentum b) angular velocity c) torque d) rotational inertia

  1. A car moves with an average speed of 60 km/hr for an hour. How far will it travel in 10 minutes?

a) 10 km b) 20 km c) 30 km d) 60 km

5. If you throw a rock straight up at 50 m/s, how long will it take for it to come back to your hand where you threw it?

a) 5 s b) 10 s c) 20 s d) 100 s

 

6. I drop a 2 kg rock from a cliff and it hits the ground 2 seconds later. How high is the cliff?

  1. 5 m b) 20 m c) 30 m d) 45 m e) 125 m

 

7. How fast is the rock going just before it hits the ground? a) 10 m/s b) 20 m/s c) 30 m/s d) 45 m/s

 

8. What is the acceleration of the rock just before it hits the ground? a) 10 m/s b) 10 m/s2 c) 5 m/s2 d) zero

 

9. How much does the rock weigh? a) 10 kg b) 2 kg c) 20 N d) 2 N e) 20 J

 

10. What is the potential energy of the rock relative to the ground just before I drop it?

a) 200 J b) 400 J c) 200N d) 400N e) zero

 

11. What is the Kinetic Energy of the rock just before it hits the ground? a) 200 J b) 400 J c) 200N d) 400N e) zero

12. What is the potential energy just when it hits the ground? a) 200 J b) 400 J c) 200N d) 400N e) zero

13. Now consider air resistance. How much air resistance must the rock experience to reach terminal velocity?

a) 20 J b) 40 J c) 20N d) 40N e) zero

14. If you throw a ball horizontally off a 80m cliff at 10m/s, how far below the horizontal is it 1second later?

a) 5 m b) 10 m c) 20 m d) no change

 

15. How far will the ball travel horizontally in 1 second? a) 10m b) 20m c) 80 m d) 100 m

 

16. How far away from the base of the cliff will the ball land when it hits the ground? a) 10m b) 20m c) 40 m d) 80 m

 

 

17. How fast would you have to throw the rock so that it never hit the Earth? a) 1 km/s b) 8 km/s c) 10 m/s d) 11 m/s

18. If you swim at 2 m/s upstream against a current flowing at 5 m/s, what is your net speed relative to the shore?

a) 10 m/s b) 3m/s c) - 2 m/s d) -3 m/s e) zero

 

19. How much work is done carrying a 10kg box up a 50m high ramp? a) 500 N b) 500 J c) 5000N d) 5000J e) zero

20. How much gravitational potential energy does the box gain in 19? a) 500 N b) 500 J c) 5000N d) 5000J e) zero

21. What is the acceleration of an object that has reached its terminal velocity? a) 10 m/s2 b) 5 m/s2 c) zero d) unknown

22. A rock and feather fall in a vacuum with the same acceleration due to gravity (10 m/s2 ) because

    1. the force of gravity acting on them is the same
    2. the ratio of weight to mass is the same for both of them

23. Granny has a mass of 50 kg and skates at 1 m/s. What is her momentum?

a) 50 m/s b) 500 m/s c) 50 kg m/s d) zero

 

24. Johnny has a mass of 50 kg and is standing on the ice. What is his momentum?

a) 50 m/s b) 500 m/s c) 50 kg m/s d) zero

 

25. Granny picks up Johnny and skates on. What is the final momentum of the system, Granny plus Johnny?

    1. 5 m/s b) 1/2 m/s c) 5 kg m/s d) 1/2 kg m/s e) zero

 

 

26. Gravity, as well as other natural phenomena such as light follow this sort of law:

a) linear b) quadratic c) inverse-square e) exponential

27. Which has the greater gravitational force on the Earth? a) Sun b) Moon c) Mars d) Jupiter

28. Which has more effect on the ocean tides on Earth? a) Sun b) Moon c) Mars d) Jupiter

29. Neap tides occur every a) spring b) full and new moon c) 1st and 3rd quarter d) eclipse

30. Consider a spinning record. Where is the velocity the greatest? a) near the axis b) near the edge c) same everywhere

31. Sally (50 kg) sits 50 cm from the fulcrum (pivot point) of a see saw as shown. Cindy sits 100 cm from the fulcrum. The see saw is in perfect balance. How much does Cindy weigh?

a) 50 kg b) 50 N c) 100 N d) 250 N e) 250 kg

 

 

32. If the force of gravity on Jupiter is 5 times as much as it is on the Earth, what is the acceleration due to gravity on Jupiter? a) 10 m/s2 b) 50 m/s2 c) 100 m/s2 d) 500 m/s2

 

 

 

33. If you weigh 1000 N on the Earth, what would you weigh on Jupiter? a) 1000 N b) 5000 kg c) 1000 N d) 5000 N

 

 

34. If the Sun shot off a HUGE solar flare and lost 1/4 of it's mass, how would the gravitational force change between the Sun and the Earth? The force would a) double b) decrease by 1/2 c) quadruple d) decrease by ¼ d) stay the same

 

35. If the distance between the Earth and the Moon doubled, the gravitational force between them

a) double b) decrease by 1/2 c) quadruple d) decrease by ¼ d) stay the same

36. The planets, including the Earth, travel around the sun in orbits that are

a) circular b) elliptical c) obtuse d) hyperbolas

37. Astronauts in the space shuttle experience weightlessness and float around because

a) there is no gravity in space b) they are in free fall c) the orbital motion of the shuttle produces anti-gravity

38. A submerged body displaces a volume of fluid equal to its _____________.

a) mass b) pressure c) weight d) density e) volume

39. The buoyant force on a body equals the ________of the fluid it displaces.

a) mass b) pressure c) weight d) density e) volume

40. An object will sink if its density is _________ than the density of water. a) greater b) less

A 1/2 liter bottle of sand is thrown in a pool of water. Ignore the mass of the bottle. Assume that the density of water is 1 kg/liter and the density of sand is 2 kg/liter.

41. What is the volume of water displaced by the bottle? a) 1/2 liter b) 1 liters c) 2 liters d) 10 liters

 

42. What is the mass of the water displaced by the bottle? a) 1/2 liter b) 1 liters c) 1/2 kg d) 2 kg e) 10 N

 

43. What is the buoyant force acting on the bottle? a) 1/2 N b) 1 N c) 5 N d) 10 N e) 10 N

 

44. What is the weight of the bottle? a) 1/2 N b) 2 N c) 2 N d) 4 N e) 10 N

 

45. What is the magnitude of the net force acting on the bottle? a) 1/2 N b) 1 N c) 2 N d) 5 N e) 10 N

46. Does the bottle sink or float? a) sink b) float c) neutral

 

The next 4 questions refer to the drawing below.

47. At which point in the orbit is the gravitational force the greatest? a) a b) b c) c d) d e) everywhere the same

48. At which point in the orbit is the potential energy the greatest? a) a b) b c) c d) d e) everywhere the same

49. At which point in the orbit is the kinetic energy the greatest? a) a b) b c) c d) d e) everywhere the same

50. At which point in the orbit is the total energy conserved? a) a b) b c) c d) d e) everywhere the same