PHYSICS 114 FINAL EXAM UPDATED QUESTIONS AND
CORRECT ANSWERS
Question:
1. The drag force:
Answer:
1. increases in magnitude
as the object's speed in-creases
2. is opposite in direction to
the velocity of the object v×’
Question:
2. Ball A with diameter d and ball B with diameter 2d are dropped from the same height. When the
two balls have the same speed, what is the ratio of the drag force on ball A to the drag force on ball
B?
Answer:
Ball A=1/2CdpAv^2 Ball B=1/2CdpAv^2 Ratio Ball A to Ball B: 1/2Cdp(d)v^2/(pv((2d)^2)/n)=1/
Question:
3. A falling object will reach its terminal speed when the magnitude of the drag force is
______________ to the magnitude of the weight force.
Answer:
equal to
Question:
4. The drag force pushes opposite your motion as you ride a bicycle. If you double your speed, what
happens to the magnitude of the drag force?
Answer:
The drag force goes up by a factor of 4.
Question:
5. Very small organisms, like paramecia or protozoa, moving around in water __________.
Answer:
almost immediately come to rest once they stop swim-ming
Question:
6. Two boxes of mass 6.0 kg and 3.0 kg are pushed across a smooth (frictionless) floor by a 18 N
force that is horizontal to the floor.
a. How many forces are exerted on Box A?
b. How many forces are exerted on box B?
c. Suppose we consider the two boxes as a single box,
box C that has a mass of 9.0 kg. What is the net force on box C?
d. What is the acceleration of box C?
e. Rank the magnitudes of the accelerations of boxes
A, B and C.
f. If all the boxes have the same acceleration, what is
the magnitude of the force that box A exerts on box B?
, g. What is the magnitude of the force that box B exerts
on box A?
Answer:
a. 4 forces
b. 3 forces
c. 18 N
d. 18/9=2.0 m/s^2
e. A=B=C
f. 18 N-(6.0 kg)(2.0
m/s^2)=6.0 N
g. (3.0 kg)(2.0 m/s^2)
Question:
7. Generally, the ______ in a ______ string or rope ______ the magnitude of the ______ pulling on
the end of the string or rope.
Answer:
1. tension
2. massless
3. equals
4. force
Question:
8. Two boxes are suspended from a rope over a pulley. Each box has weight 50 N. What is the tension
in the rope?
Answer:
50 N
Question:
9. For an object in uniform circular motion, what can you say about the directions of the velocity,
acceleration, and net force vectors?
Answer:
The velocity vector is per-pendicular to the accelera-tion vector; the acceleration vector is parallel to
the net force vector.
Question:
10. In the video, a car rounding a corner and a car going over the crest of a hill are both presented as
examples of...
Answer:
Uniform circular motion
Question:
11. According to the convention used in the textbook, the angular position θ is positive when
measured:
Answer:
counterclockwise from the positive x-axis.
Question:
12. How many radians are equivalent to 150°? Give your answer to two signficant figures.
CORRECT ANSWERS
Question:
1. The drag force:
Answer:
1. increases in magnitude
as the object's speed in-creases
2. is opposite in direction to
the velocity of the object v×’
Question:
2. Ball A with diameter d and ball B with diameter 2d are dropped from the same height. When the
two balls have the same speed, what is the ratio of the drag force on ball A to the drag force on ball
B?
Answer:
Ball A=1/2CdpAv^2 Ball B=1/2CdpAv^2 Ratio Ball A to Ball B: 1/2Cdp(d)v^2/(pv((2d)^2)/n)=1/
Question:
3. A falling object will reach its terminal speed when the magnitude of the drag force is
______________ to the magnitude of the weight force.
Answer:
equal to
Question:
4. The drag force pushes opposite your motion as you ride a bicycle. If you double your speed, what
happens to the magnitude of the drag force?
Answer:
The drag force goes up by a factor of 4.
Question:
5. Very small organisms, like paramecia or protozoa, moving around in water __________.
Answer:
almost immediately come to rest once they stop swim-ming
Question:
6. Two boxes of mass 6.0 kg and 3.0 kg are pushed across a smooth (frictionless) floor by a 18 N
force that is horizontal to the floor.
a. How many forces are exerted on Box A?
b. How many forces are exerted on box B?
c. Suppose we consider the two boxes as a single box,
box C that has a mass of 9.0 kg. What is the net force on box C?
d. What is the acceleration of box C?
e. Rank the magnitudes of the accelerations of boxes
A, B and C.
f. If all the boxes have the same acceleration, what is
the magnitude of the force that box A exerts on box B?
, g. What is the magnitude of the force that box B exerts
on box A?
Answer:
a. 4 forces
b. 3 forces
c. 18 N
d. 18/9=2.0 m/s^2
e. A=B=C
f. 18 N-(6.0 kg)(2.0
m/s^2)=6.0 N
g. (3.0 kg)(2.0 m/s^2)
Question:
7. Generally, the ______ in a ______ string or rope ______ the magnitude of the ______ pulling on
the end of the string or rope.
Answer:
1. tension
2. massless
3. equals
4. force
Question:
8. Two boxes are suspended from a rope over a pulley. Each box has weight 50 N. What is the tension
in the rope?
Answer:
50 N
Question:
9. For an object in uniform circular motion, what can you say about the directions of the velocity,
acceleration, and net force vectors?
Answer:
The velocity vector is per-pendicular to the accelera-tion vector; the acceleration vector is parallel to
the net force vector.
Question:
10. In the video, a car rounding a corner and a car going over the crest of a hill are both presented as
examples of...
Answer:
Uniform circular motion
Question:
11. According to the convention used in the textbook, the angular position θ is positive when
measured:
Answer:
counterclockwise from the positive x-axis.
Question:
12. How many radians are equivalent to 150°? Give your answer to two signficant figures.
