Midterm Review
B
A
C
D
1. During which interval(s) did the object move in the negative y direction?
a. Only during interval B
b. Only during interval C
c. Only during interval D
d. During both intervals C and D
e. The object never moved in the negative x direction
2. Which segment(s) of the graph represent(s) a constant velocity of +1.0 m/s?
a. A
c. C
b. B
d. D
e. A and C
3. For which one of the following situations will the path length equal the magnitude of the displacement?
a. A ball is rolling down and inclined plane.
b. A jogger is running around a circular path.
c. A train travels 5 miles east; and then, it stops and travels 2 miles west.
d. A ball on the end of a string is moving in a vertical circle.
e. A ball rises and falls after being thrown straight up from the earth’s surface.
4. A physics student adds two displacement vectors with magnitudes of 8.0 km and 6.0 km. Which one of the following
statements is true concerning the magnitude of the resultant displacement?
a. It must be 14.0 km.
b. It could have any value between 2.0 km and 14.0 km depending on how the vectors are oriented.
c. No conclusion can be reached without knowing the directions of the vectors.
d. It could be zero depending on how the vectors are oriented.
e. It must be 10.0 km.
5. A rock is thrown vertically upward from the surface of the earth. The rock rises to some maximum height and falls
back towards the surface of the earth. Which one of the following statements concerning this situation is true if air
resistance is neglected?
a. The acceleration of the ball is zero when the ball is at its highest point.
b. The speed of the ball is negative while the ball falls back toward the earth.
c. As the ball rises, its acceleration vector points upward.
d. The velocity and acceleration of the ball always point in the same direction.
e. The ball is a freely falling body for the duration of its flight.
6. A certain string just breaks when it is under 400 N of tension. A boy uses this string to whirl a 10-kg stone in a
horizontal circle of radius 10 m. The boy continuously increases the speed of the stone. At approximately what speed
will the string break?
a. 10 m/s
c. 20 m/s
e. 100 m/s
b. 400 m/s
d. 80 m/s
7. Which force is responsible for holding a car in an unbanked curve?
a. the reaction force to the car’s weight
b. the force of friction
c. the car’s weight
d. the horizontal component of the normal force
e. the vertical component of the normal force
8. The horizontal velocity of the ball when it is in the air
a. Is decreasing
b. Stays the same
9. The vertical velocity of the ball, that is launched horizontally, when it is in the air
a. Is decreasing
b. Stays the same
c.
Is increasing
c.
Is increasing
D
B
C
E
A
10. In which segments(s) of the graph does the object’s average velocity (measured from t = 0) decrease with time?
a. BC only
c. DE only
e. AB and CD
b. AB only
d. BC and DE
11. In which segment(s) of the graph does the object have the highest speed?
a. DE
c. AB and CD
b. BC
d. AB
e. CD
12. At which time(s) does the object reverse its direction of motion?
a. 5 s
c. 1 s
b. 2 s
d. 2 s and 5 s
e. 1 s and 2 s
P
30˚
13. Which one of the following expressions gives the magnitude of the force P in SI units? Assume the block is moving at
a constant velocity and the frictional force is 10 N.
a. 10(sin 30)
c. 10/(cos 30)
e. 10/(sin 30)
b. 10(cos 30)
d. tan 30
14. Complete the following statement: The magnitude f the normal force could be reduced by
a. Decreasing the velocity of the block.
d. Increasing the angle made by the rope.
b. Increasing the speed of the block.
e. Decreasing the coefficient of kinetic friction.
c. Decreasing the angle made by the rope.
15. Which one of the following actions will increase the frictional force on the block?
a. Decreasing the contact surface area
d. Decreasing the speed of the block
b. Increasing the angle made by the rope
e. Increasing the weight of the block
c. Increasing the contact surface area
16. In an experiment with a block of wood on an inclined plane, which has a height of 1.0 m and a length (horizontal
component) of 4 m, the following observations are made:
1. If the block is placed on the inclined plane, it remains there at rest.
2. If the block is given a small push, it will accelerate toward the bottom of the incline without
any further pushing.
Which is the best conclusion that can be drawn from these observations?
a. The coefficient of this kinetic friction must be negative.
b. Both coefficients of friction must be greater than 0.25.
c. The coefficient of static friction is greater than 0.25 while the coefficient of kinetic friction is less than 0.25.
d. Both coefficients of friction must be less than 0.25.
e. The coefficients of static friction must be less than the coefficient of kinetic friction.
17. Two point masses m and M are separated by distance d. if the separation d remains fixed and the masses are
increased to the values 3m and 3M respectively, how does the gravitational fore between them change?
a. The force will be nine times as great.
b. The force will be one-ninth as great.
c. The force will be one-third as great.
d. It is impossible to determine without knowing the numerical values of m, M, and d.
e. The force will be three times as great.
18. Which one of the following statements concerning the two “gravitational constants”
G, the universal constant, and g the magnitude of the acceleration due to gravity is
true?
a. The values of g and G do not depend on location.
b. The values of g and G depend on location.
c. The value of G is the same everywhere in the universe, but the value of g is not.
d. The value of g is the same everywhere in the universe, but the value of G is not.
e. The values of g and G are equal on the surface of any planet, but in general, vary with location in the
universe.
19. An object moving along a straight line is decelerating. Which one of the following statements concerning the object’s
acceleration is necessarily true?
a. An object that is decelerating has a negative acceleration.
b. The direction of the acceleration is in the direction opposite to that of the velocity.
c. The acceleration changes as the object moves along the line.
d. The value of the acceleration is positive.
e. The direction of the acceleration is in the same direction as the displacement.
A block is pulled along a rough level surface at constant speed by the force P. The figure shows the free-body
diagram for the block.
FN
f
P
mg
Fn represents the normal force on the block; f represents the force of kinetic friction.
20. What is the magnitude of Fn?
a. 2mg
b. f
c. This cannot be determined from the information given.
d. mg
e. P
21. A 2.0-N rock slides on a frictionless inclined plane. Which one of the following statements is true concerning the
normal force that the plane exerts on the rock?
a. The normal force is greater than 2.0 N.
b. It increases as the angle of inclination, , is increased.
c. The normal force is zero.
d. The normal force is less than 2.0 N, but greater than zero.
e. The normal force is 2.0 N.
22. A turtle running 2 m/s to the left slows down. Choose the answer that best describes the motion.
a. Acceleration +, Velocity - c. Acceleration - , Velocity b. Acceleration +, Velocity + d. Acceleration - , Velocity +
23. An ostrich walking to the right and picking up speed. Choose the following answer that best describes the motion.
a. Acceleration +, Velocity - c. Acceleration - , Velocity b. Acceleration +, Velocity + d. Acceleration - , Velocity +
24. Mr. P jumping. (1st half of the trip) Choose the following answer that best describes his motion.
a. Acceleration +, Velocity - c. Acceleration - , Velocity b. Acceleration +, Velocity + d. Acceleration - , Velocity +
25. Mr. P jumping. (Second half of the trip) Choose the answer that best describes his motion.
a. Acceleration +, Velocity - c. Acceleration - , Velocity b. Acceleration +, Velocity + d. Acceleration - , Velocity +
26. If Mr. P launches himself upward at a greater initial velocity, which of the following will occur?
a. His displacement will be greater.
b. His speed when he returns to the ground will be greater.
c. His total time in flight will increase.
d. His total time in flight will decrease.
e. His acceleration will increase.
27. A toy car begins with an initial velocity (Vi) in the southward direction and continues for time t. After it travels for t
seconds it slows at a rate of a for t'. Find the toy cars total displacement in terms of Vi, t, t', and Vf.
a. -Vit-Vit'+1/2(Vf+Vi)t c. -Vit-Vit'+1/2at^2
b. Vit+Vit'+1/2(Vf+Vi)t d. -Vit-Vit'+1/2(Vf+Vi)t^2
28. Choose the Conservation of energy equation that correctly matches the energy transfer from point A on the
rollercoaster to point C on the roller coast if the it starts from rest and it is frictionless.
a. Ug = KE + Ug
c. Ug = KE
b. KE + Ug = KE + Ug d. Ug = Ug
29. Choose the correct COE eqn if the rollercoaster starts at point A and travels to point D. The rollercoaster is not
starting from rest. Assume friction.
a. Wf + KE = Ug
c. Wf + KE + Ug = KE + Ug
b. KE + Ug = KE + Ug + Wf d. Ug = Ug + KE + Wf
30. If the box starts at the bottom of the incline, compressing the spring fully, what is the conservation of energy equation
when the box is halfway up the incline. Assume friction.
a. Ue = KE + Ug c. Ue = KE + Ug + Wf
b. Ue = KE + Wf d. Wf + Ue = KE
31. What is the COE eqn if the box starts at the top of the ramp, not moving, and slides down until it just touches touches
the spring? It does not compress the spring and there IS friction.
a. Ug = KE - Wf - Ug
c. Ug = KE + Wf
b. Wf + Ug = KE + Ug d. Ug - Wf = KE + Ug
32. Which of the following situations requires the least amount of force to get a 20 kg box to the top of 4 m?
a. Lifting the block to the top of 4 m.
b. Pushing the block up a 30 degree incline up to 4m.
c. Pushing the block up a 60 degree incline up to 4m.
d. None of the above.
33. A projectile has an initial velocity Vo at an angle θo above the horizontal. It reaches the highest point of its trajectory
in a time t after launch. The highest point is a vertical distance hmax and a horizontal distance d from the firing point.
All of the following statements are true except:
a. hmax=(Vo sinθo)^2 /-2g
b. d=Vo t cosθo
c. t= (Vocosθo) /g
34. If ball A was launched horizontally at a height of 1 m and ball B was launched at a height of 3 m at the same velocity
as A then which ball would hit the ground first?
a. Ball a
c. Both would land at the same time.
b. Ball b
35. Refer to the situation above. Which ball would have the greatest horizontal range?
a. Ball a
c. Both would have the same horizontal range.
b. Ball b
36. The horizontal acceleration of the ball when it is in the air is
a. Increasing
b. Decreasing
c.
0
d. -9.8 m/s2
37. The vertical acceleration of a ball in the air is
a. Increasing
b. Decreasing
c.
0
d. -9.8 m/s2
38. If a table was 1 meter tall how long would it take a ball to hit the ground if it was launched horizontally off the table
with a velocity of 0.5 m/s?
a. .20 s
b. .32 s
c. .45 s
39. Referring to the same information as the previous problem (a table 1 m tall, ball launch horizontally at 0.5 m/s) what
range would the ball travel before it hits the ground?
a. .10 m
b. .16 m
c. .23 m
40. If one ball was dropped at the same time the another ball was launched off the table horizontally, which ball would hit
the ground first?
a. both would land at the same time
b. ball launched
c. ball dropped
41. If two balls were launched horizontally with the same velocity and at the same height but ball A was 1 kg and ball B
was 10 kg, which ball would hit the ground first?
a. Ball A
b. Ball B
c. both would land at the same time
42. Is which situation is the rope most likely to break?
43. In which situation will the box be most difficult to move? (assume there is friction.)
44. For the following situation, which picture shows the correct force diagram for finding the minimum tension to keep the
box on the incline without it moving?
45. If, from a height of 75 m, Mr. Davies dropped one of the cannon balls 0.7 seconds before the other, with what velocity
would the second ball have to be thrown downward to reach the round at the same time as the first? (round to two
decimal places)
46. Suppose that an airplane flying at 70 m/s, at a height of 350 m, dropped a sack of rice to some villagers in Sudan.
How far from the point of release would the sack have traveled when it struck the ground? (round to the nearest whole
number)
47. A football is kicked at an angle of 38° and travels a distance of 15 m before hitting the ground. What was the initial
speed of the ball? (round to one decimal places)
48. The energizer bunny races a turtle who travels at a constant velocity of 1.8 m/s. If the race track is 1.2 km long, and
the energizer bunny is capable of maintaining a constant rate of acceleration of .8 m/s 2 how much time can the bunny
wait before he needs to start acceleration so that he beats the turtle by .5 m?
49. For the following situation, which answer choice best shows the force diagram for the maximum tension you can apply
before moving the box up the slope?
50. For the following situation, choose the force diagram that best represents the 1 kg mass where mass M is the
minimum it needs to be to keep the system static.
51. For the following situation, choose the force diagram that best represents the 1 kg mass where mass M is
the maximum it can be to keep the system static.
52. If the height of point A is 50 m and the rollercoaster starts from rest, how fast would it be travelling at point C at a
height of 30 m? Assume the track is frictionless. (Round to 3 sig figs)
53. If a 5 kg block starts 3 m up a 30º incline that has a coefficient of kinetic friction of .15, how far would it compress a
spring with a spring constant of 2500 N/m, that is placed at the bottom of the ramp? Assume that when the spring is
compressed the block is at the bottom of the incline. (Round to 3 significant figures)
54. In the following situation solve for the maximum mass that M can represent while still keeping the masses static.
Round to three significant figures.
55. A pack of nerds, traveling at 7 m/s see a teacher 20 m away. If the nerds catch the teacher 18.2 m from where he
started to accelerate, what was the teacher’s rate of acceleration assuming he started from rest?
56. If a ball is kicked to the top of a 7.2 m roof with an initial velocity of 43 m/s at 60 degrees, what is the ball’s velocity
when it hits the roof?
57. Determine how far from the edge of the ramp the block will land if m = 105 kg, vo=0 at the bottom of the ramp, if
μ=.22, FA=1350N and is only applied while the object is on the ramp, the length of the incline is 2.5 m, θ=40, and it is
10.1m in height.
FA
10.1 m
10˚
2.5
mm
M
θ
s
58. Find the minimum value of m 2 to maintain equilibrium in terms of μ, m 1, φ, and θ.
φ
M1
M2
μ
θ
59. Find the mass of m 3 needed to keep the block in equilibrium on the incline if m 2=105000 kg, m1 = 50000kg, and
θ=58˚ and μ=.35.
M3
1.25 m
M2
.75m
M1
18˚
θ