Download ExamView - Quiz 6--Gravity, Circular motion, Torque.tst

Name: ________________________ Class: ___________________ Date: __________
ID: A
Quiz 6--Work, Gravitation, Circular Motion, Torque. (60 pts available, 50 points possible)
Multiple Choice, 2 point each
Identify the choice that best completes the statement or answers the question.
1.
What is the term for the net force directed toward the center of an object’s circular path?
a. centrifugal force b. orbital force c. centripetal force d. circular force
2.
A car on a roller coaster loaded with passengers has a mass of 2.0 × 10 3 kg. At the lowest point of the track, the radius of curvature of the
track is 24 m and the roller car has a tangential speed of 17 m/s. What centripetal force is exerted on the roller car at the lowest point?
a. 2.4 × 101 N b. 2.4 × 10 4 N c. 2.4 × 103 N d. 2.4 × 102 N
3.
A horizontal force of 200 N is applied to move a 55 kg television set across a 10 m level surface. What is the work done by the 200 N
force on the television set?
a. 11000 J b. 550 J c. 2000 J d. 6000 J
4.
What is the common formula for work? Assume that W is the work, F is a constant force, ∆v is the change in velocity, and d is the
displacement.
a. W = Fd 2 b. W = F∆v c. W = Fd d. W = F2 d
5.
A car on a roller coaster loaded with passengers has a mass of 2.0 × 10 3 kg. At the lowest point of the track, the radius of curvature of the
track is 24 m and the roller car has a tangential speed of 17 m/s. What is the centripetal acceleration of the roller car at the lowest point on
the track?
a. 10 m/s 2 b. 12 m/s 2 c. 11 m/s 2 d. 14 m/s 2
6.
How much work is done on a bookshelf being pulled 5.00 m at an angle of 37.0° from the horizontal? The magnitude of the component of
the force that does the work is 43.0 N.
a. 20.5 J b. 21.5 J c. 205 J d. 215 J
7.
Which of the following energy forms is associated with an object in motion?
a. kinetic energy b. nonmechanical energy c. potential energy d. elastic potential energy
8.
A professional skier starts from rest and reaches a speed of 56 m/s on a ski slope angled 30.0° above the horizontal. Using the
work-kinetic energy theorem and disregarding friction, find the minimum distance along the slope the skier would have to travel in order
to reach this speed.
a. 30 m b. 300 m c. 320 m d. 32 m
9.
A 35 kg child moves with uniform circular motion while riding a horse on a carousel. The horse is 3.2 m from the carousel’s axis of
rotation and has a tangential speed of 2.6 m/s. What is the child’s centripetal acceleration?
a. 21 m/s^2 b. 0.21 m/s^2 c. 210 m/s^2 d. 2.1 m/s^2
10.
If you want to open a swinging door with the least amount of force, where should you push on the door?
a. in the middle b. as far from the hinges as possible c. close to the hinges d. It does not matter where you push.
11.
Which of the following quantities measures the ability of a force to rotate or accelerate an object around an axis?
a. axis of rotation b. lever arm c. torque d. tangential force
12.
Which of the following can be a centripetal force?
a. gravity b. tension c. friction d. all of the above
13.
The centripetal force on an object in circular motion is
a. in the same direction as the centripetal acceleration. b. in the direction opposite the tangential speed. c. in the same direction as
the tangential speed. d. in the direction opposite the centripetal acceleration.
14.
A 61.5 kg student sits at a desk 1.25 m away from a 70.0 kg student. What is the magnitude of the gravitational force between the two
students? (G = 6.673 × 10 −11 N•m 2 /kg 2 )
a. 1.00 × 10 −7 N b. 1.84 × 10 7 N c. 1.84 × 10 −17 N d. 1.84 × 10 −7 N
1
Name: ________________________
ID: A
15.
A worker pushes a box with a horizontal force of 50.0 N over a level distance of 5.0 m. If a frictional force of 43 N acts on the box in a
direction opposite to that of the worker, what net work is done on the box?
a. 3.5 J b. 35 J c. 32 J d. 3.2 J
16.
A 35 kg child moves with uniform circular motion while riding a horse on a carousel. The horse is 3.2 m from the carousel’s axis of
rotation and has a tangential speed of 2.6 m/s. What is the centripetal force on the child?
a. 74 N b. 740 N c. 0.74 N d. 7.4 N
A child rides a bicycle in a circular path with a radius of 2.0 m. The tangential speed of the bicycle is 2.0 m/s. The combined mass of the
bicycle and the child is 43 kg.
17.
What is the magnitude of the centripetal force on the bicycle?
a. 86 N b. 43 N c. 4.0 N d. 3.7 kN
18.
What is the magnitude of the bicycle’s centripetal acceleration?
a. 8.0 m/s2 b. 2.0 m/s2 c. 1.0 m/s2 d. 4.0 m/s2
19.
What kind of force provides the centripetal force on the bicycle?
a. normal force b. friction c. air resistance d. gravitational force
20.
Gravitational potential energy is always measured in relation to
a. a zero level. b. kinetic energy. c. mechanical energy. d. total potential energy.
21.
When an object is moving with uniform circular motion, the centripetal acceleration of the object
a. is directed toward the center of motion. b. is zero. c. is perpendicular to the plane of motion. d. is circular.
22.
Which of the following is the rate at which work is done?
a. power b. mechanical energy c. kinetic energy d. potential energy
23.
Which of the following equations expresses Newton’s law of universal gravitation?
a. F c =
mv t 2
r
b. F g = G
m1 m2
r
2
c. F g =
m1 m2
r
d. g = G
mE
r2
24.
Work is done when
a. the displacement is not zero. b. the force and displacement are perpendicular. c. the force is zero. d. the displacement is zero.
25.
When calculating the gravitational force between two extended bodies, you should measure the distance
a. from the center of one body to the closest point on the other body. b. from the center of each body. c. from the most distant points
on each body. d. from the closest points on each body.
26.
A force does work on an object if a component of the force
a. parallel to the displacement of the object moves the object along a path that returns the object to its starting position.
b. perpendicular to the displacement of the object moves the object along a path that returns the object to its starting position. c. is
perpendicular to the displacement of the object. d. is parallel to the displacement of the object.
27.
Which of the following equations expresses the work-kinetic energy theorem?
a. W net = ∆PE b. Wnet = ∆KE c. ∆W = ∆KE d. ME i = ME f
28.
A child moving at constant velocity carries a 2 N ice-cream cone 1 m across a level surface. What is the net work done on the ice-cream
cone?
a. 20 J b. 2 J c. 0.5 J d. 0 J
29.
What is the efficiency of a machine that requires 1.00 × 10 2 J of input energy to do 35 J of work?
a. 35% b. 65% c. 29% d. 2.9%
30.
Which of the following energy forms is associated with an object due to its position?
a. total energy b. positional energy c. potential energy d. kinetic energy
2
ID: A
Quiz 6--Work, Gravitation, Circular Motion, Torque. (60 pts available, 50 points possible)
Answer Section
MULTIPLE CHOICE
1.
2.
ANS:
ANS:
C
B
PTS:
1
DIF:
I
OBJ:
7-1.2
5-1.4
I
OBJ:
5-1.2
2.4 × 10 4 N
Given
m = 2.0 × 10 3 kg
v t = 17 m/s
r = 24 m
Solution
ÊÁ
ˆ˜
3
2
ÁÁ 2.0 × 10 kg ˜˜ ( 17 m/s )
mv t 2
Ë
¯
Fc =
=
= 2.4 × 10 4 N
r
24 m
3.
PTS:
ANS:
1
C
Given
F = 200 N
d = 10 m
Solution
W = Fd = ( 200 N ) ( 10 m ) = 2 × 10 3 J
4.
5.
PTS:
ANS:
ANS:
1
C
B
DIF:
PTS:
IIIA
1
OBJ:
DIF:
12 m/s 2
Given
v t = 17 m/s
r = 24 m
Solution
ac =
PTS:
vt 2
( 17 m/s ) 2
=
= 12 m/s 2
r
24 m
1
1
ID: A
6.
ANS:
215 J
D
Given
F = 43.0 N
d = 5.00 m
Solution
W = Fd = ( 43.0 N ) ( 5.00 m ) = 215 J
7.
8.
PTS: 1
ANS: A
ANS: C
320 m
PTS:
1
DIF:
I
OBJ:
5-2.1
DIF:
DIF:
I
I
OBJ:
OBJ:
7-4.1
7-4.1
Given
v i = 0 m/s
v f = 56 m/s
θ = 30.0°
g = 9.81 m/s 2
Solution
Wnet = ∆KE
Wnet = Fd = (mg sin θ)d
1
1
∆KE = KE f − KEi = 2 mv f 2 − 0 = 2 mv f 2
1
mgd sin θ = 2 mv f 2
d=
d=
9.
vf2
2g sin θ
( 56 m/s ) 2
= 3.2 × 10 2 m
ÊÁ
ˆ˜
2
( 2 ) ÁÁÁ 9.81 m/s ˜˜˜ ( sin 30.0° )
Ë
¯
PTS:
ANS:
1
D
2.1 m/s 2
Given
v t = 2.6 m/s
r = 3.2 m
Solution
ac =
10.
11.
PTS:
ANS:
ANS:
vt 2
( 2.6 m/s ) 2
=
= 2.1 m/s 2
r
3.2 m
1
B
C
PTS:
PTS:
1
1
2
ID: A
12.
13.
14.
15.
ANS:
ANS:
ANS:
ANS:
35 J
D
A
D
B
PTS:
PTS:
PTS:
1
1
1
DIF:
DIF:
I
I
OBJ:
OBJ:
Given
F w = 50.0 N
F k = −43 N
d = 5.0 m
Solution
ÍÈ
˙˘
Wnet = F net d = ÊÁË Fw + F k ˆ˜¯ d = ÍÍÎ ( 50.0 N ) + ( −43 N ) ˙˙˚ ( 5.0 m ) = 35 J
16.
PTS:
ANS:
74 N
1
A
Given
m = 35 kg
v t = 2.6 m/s
r = 3.2 m
Solution
ÁÊ 35 kg ˜ˆ ( 2.6 m/s ) 2
mv t 2
Ë
¯
Fc =
=
= 74 N
r
3.2 m
17.
PTS:
ANS:
1
A
Given
m = 43 kg
v t = 2.0 m/s
r = 2.0 m
Solution
Fc =
PTS:
ÊÁ 43 kg ˜ˆ ( 2.0 m/s ) 2
mv t 2
Ë
¯
=
= 86 N
r
2.0 m
1
DIF:
IIIA
OBJ:
7-1.2
3
7-1.2
7-1.2
ID: A
18.
ANS:
B
Given
v t = 2.0 m/s
r = 2.0 m
Solution
ac =
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
vt 2
( 2.0 m/s ) 2
=
= 2.0 m/s 2
r
2.0 m
PTS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
1
B
A
A
A
B
A
B
D
B
D
A
DIF:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
IIIA
1
1
1
1
1
1
1
1
1
1
OBJ:
DIF:
DIF:
DIF:
DIF:
DIF:
DIF:
DIF:
DIF:
DIF:
DIF:
7-1.1
II
I
I
I
I
I
I
I
I
II
OBJ:
OBJ:
OBJ:
OBJ:
OBJ:
OBJ:
OBJ:
OBJ:
OBJ:
OBJ:
7-1.2
5-2.5
7-1.1
5-4.1
7-2.2
5-1.2
7-2.2
5-1.2
5-2.3
5-1.4
OBJ:
DIF:
7-4.4
I
OBJ:
5-2.1
Given
W in = 1.00 × 10 2 J
W out = 35 J
Solution
W out
35 J
eff =
=
= 0.35 = 35%
Win
1.00 × 10 2 J
30.
PTS:
ANS:
1
C
DIF:
PTS:
IIIA
1
4
Name: ________________________ Class: ___________________ Date: __________
ID: B
Quiz 6--Work, Gravitation, Circular Motion, Torque. (60 pts available, 50 points possible)
Multiple Choice, 2 point each
Identify the choice that best completes the statement or answers the question.
1.
When calculating the gravitational force between two extended bodies, you should measure the distance
a. from the closest points on each body. b. from the center of one body to the closest point on the other body. c. from the center of
each body. d. from the most distant points on each body.
2.
A 35 kg child moves with uniform circular motion while riding a horse on a carousel. The horse is 3.2 m from the carousel’s axis of
rotation and has a tangential speed of 2.6 m/s. What is the centripetal force on the child?
a. 0.74 N b. 740 N c. 7.4 N d. 74 N
3.
What is the common formula for work? Assume that W is the work, F is a constant force, ∆v is the change in velocity, and d is the
displacement.
a. W = Fd 2 b. W = F∆v c. W = F2 d d. W = Fd
A child rides a bicycle in a circular path with a radius of 2.0 m. The tangential speed of the bicycle is 2.0 m/s. The combined mass of the
bicycle and the child is 43 kg.
4.
What is the magnitude of the bicycle’s centripetal acceleration?
a. 2.0 m/s2 b. 8.0 m/s2 c. 4.0 m/s2 d. 1.0 m/s2
5.
What kind of force provides the centripetal force on the bicycle?
a. air resistance b. friction c. gravitational force d. normal force
6.
What is the magnitude of the centripetal force on the bicycle?
a. 86 N b. 4.0 N c. 3.7 kN d. 43 N
7.
Which of the following equations expresses Newton’s law of universal gravitation?
a. F g =
m1 m2
r
b. F g = G
m1 m2
r
2
c. F c =
mv t 2
r
d. g = G
mE
r2
8.
A horizontal force of 200 N is applied to move a 55 kg television set across a 10 m level surface. What is the work done by the 200 N
force on the television set?
a. 550 J b. 6000 J c. 11000 J d. 2000 J
9.
Gravitational potential energy is always measured in relation to
a. mechanical energy. b. kinetic energy. c. a zero level. d. total potential energy.
10.
Which of the following is the rate at which work is done?
a. mechanical energy b. potential energy c. kinetic energy d. power
11.
The centripetal force on an object in circular motion is
a. in the same direction as the tangential speed. b. in the direction opposite the tangential speed. c. in the same direction as the
centripetal acceleration. d. in the direction opposite the centripetal acceleration.
12.
When an object is moving with uniform circular motion, the centripetal acceleration of the object
a. is directed toward the center of motion. b. is zero. c. is circular. d. is perpendicular to the plane of motion.
13.
A 61.5 kg student sits at a desk 1.25 m away from a 70.0 kg student. What is the magnitude of the gravitational force between the two
students? (G = 6.673 × 10 −11 N•m 2 /kg 2 )
a. 1.84 × 10 −7 N b. 1.84 × 10 7 N c. 1.00 × 10 −7 N d. 1.84 × 10 −17 N
14.
What is the term for the net force directed toward the center of an object’s circular path?
a. circular force b. orbital force c. centrifugal force d. centripetal force
1
Name: ________________________
ID: B
15.
A force does work on an object if a component of the force
a. parallel to the displacement of the object moves the object along a path that returns the object to its starting position.
b. perpendicular to the displacement of the object moves the object along a path that returns the object to its starting position. c. is
parallel to the displacement of the object. d. is perpendicular to the displacement of the object.
16.
A worker pushes a box with a horizontal force of 50.0 N over a level distance of 5.0 m. If a frictional force of 43 N acts on the box in a
direction opposite to that of the worker, what net work is done on the box?
a. 3.5 J b. 3.2 J c. 32 J d. 35 J
17.
How much work is done on a bookshelf being pulled 5.00 m at an angle of 37.0° from the horizontal? The magnitude of the component of
the force that does the work is 43.0 N.
a. 215 J b. 21.5 J c. 205 J d. 20.5 J
18.
Which of the following quantities measures the ability of a force to rotate or accelerate an object around an axis?
a. tangential force b. lever arm c. torque d. axis of rotation
19.
A professional skier starts from rest and reaches a speed of 56 m/s on a ski slope angled 30.0° above the horizontal. Using the
work-kinetic energy theorem and disregarding friction, find the minimum distance along the slope the skier would have to travel in order
to reach this speed.
a. 300 m b. 30 m c. 320 m d. 32 m
20.
Work is done when
a. the displacement is zero. b. the displacement is not zero. c. the force and displacement are perpendicular. d. the force is zero.
21.
If you want to open a swinging door with the least amount of force, where should you push on the door?
a. in the middle b. It does not matter where you push. c. close to the hinges d. as far from the hinges as possible
22.
A car on a roller coaster loaded with passengers has a mass of 2.0 × 10 3 kg. At the lowest point of the track, the radius of curvature of the
track is 24 m and the roller car has a tangential speed of 17 m/s. What is the centripetal acceleration of the roller car at the lowest point on
the track?
a. 10 m/s 2 b. 11 m/s 2 c. 12 m/s 2 d. 14 m/s 2
23.
A child moving at constant velocity carries a 2 N ice-cream cone 1 m across a level surface. What is the net work done on the ice-cream
cone?
a. 0 J b. 20 J c. 0.5 J d. 2 J
24.
Which of the following can be a centripetal force?
a. tension b. friction c. gravity d. all of the above
25.
Which of the following equations expresses the work-kinetic energy theorem?
a. Wnet = ∆KE b. W net = ∆PE c. ∆W = ∆KE d. ME i = ME f
26.
What is the efficiency of a machine that requires 1.00 × 10 2 J of input energy to do 35 J of work?
a. 29% b. 35% c. 65% d. 2.9%
27.
A 35 kg child moves with uniform circular motion while riding a horse on a carousel. The horse is 3.2 m from the carousel’s axis of
rotation and has a tangential speed of 2.6 m/s. What is the child’s centripetal acceleration?
a. 21 m/s^2 b. 210 m/s^2 c. 0.21 m/s^2 d. 2.1 m/s^2
28.
Which of the following energy forms is associated with an object due to its position?
a. kinetic energy b. positional energy c. potential energy d. total energy
29.
A car on a roller coaster loaded with passengers has a mass of 2.0 × 10 3 kg. At the lowest point of the track, the radius of curvature of the
track is 24 m and the roller car has a tangential speed of 17 m/s. What centripetal force is exerted on the roller car at the lowest point?
a. 2.4 × 101 N b. 2.4 × 103 N c. 2.4 × 10 4 N d. 2.4 × 102 N
30.
Which of the following energy forms is associated with an object in motion?
a. elastic potential energy b. potential energy c. nonmechanical energy d. kinetic energy
2
ID: B
Quiz 6--Work, Gravitation, Circular Motion, Torque. (60 pts available, 50 points possible)
Answer Section
MULTIPLE CHOICE
1.
2.
ANS:
ANS:
74 N
C
D
PTS:
1
DIF:
I
OBJ:
7-2.2
1
DIF:
I
OBJ:
5-1.2
IIIA
1
OBJ:
DIF:
7-1.1
II
OBJ:
7-1.2
OBJ:
DIF:
7-1.2
I
OBJ:
7-2.2
Given
m = 35 kg
v t = 2.6 m/s
r = 3.2 m
Solution
ÁÊ 35 kg ˜ˆ ( 2.6 m/s ) 2
mv t 2
Ë
¯
Fc =
=
= 74 N
r
3.2 m
3.
4.
PTS:
ANS:
ANS:
1
D
A
PTS:
Given
v t = 2.0 m/s
r = 2.0 m
Solution
ac =
5.
6.
vt 2
( 2.0 m/s ) 2
=
= 2.0 m/s 2
r
2.0 m
PTS:
ANS:
ANS:
1
B
A
DIF:
PTS:
Given
m = 43 kg
v t = 2.0 m/s
r = 2.0 m
Solution
ÊÁ 43 kg ˜ˆ ( 2.0 m/s ) 2
mv t 2
Ë
¯
Fc =
=
= 86 N
r
2.0 m
7.
PTS:
ANS:
1
B
DIF:
PTS:
IIIA
1
1
ID: B
8.
ANS:
D
Given
F = 200 N
d = 10 m
Solution
W = Fd = ( 200 N ) ( 10 m ) = 2 × 10 3 J
9.
10.
11.
12.
13.
14.
15.
16.
PTS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
35 J
1
C
D
C
A
A
D
C
D
DIF:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
PTS:
IIIA
1
1
1
1
1
1
1
OBJ:
DIF:
DIF:
DIF:
DIF:
5-1.4
I
I
I
I
OBJ:
OBJ:
OBJ:
OBJ:
5-2.5
5-4.1
7-1.2
7-1.1
DIF:
DIF:
I
I
OBJ:
OBJ:
7-1.2
5-1.2
OBJ:
7-4.1
Given
F w = 50.0 N
F k = −43 N
d = 5.0 m
Solution
Wnet = F net d = ÊÁË Fw + F k ˆ˜¯ d =
17.
PTS:
ANS:
215 J
ÈÍ
˘
ÍÍ ( 50.0 N ) + ( −43 N ) ˙˙˙ ( 5.0 m ) = 35 J
Î
˚
1
A
Given
F = 43.0 N
d = 5.00 m
Solution
W = Fd = ( 43.0 N ) ( 5.00 m ) = 215 J
18.
PTS:
ANS:
1
C
PTS:
1
DIF:
I
2
ID: B
19.
ANS: C
320 m
Given
v i = 0 m/s
v f = 56 m/s
θ = 30.0°
g = 9.81 m/s 2
Solution
Wnet = ∆KE
Wnet = Fd = (mg sin θ)d
∆KE = KE f − KEi =
mgd sin θ =
v
d=
d=
20.
21.
22.
1
2
mv f
1
2
mv f 2 − 0 =
1
2
mv f
2
2
2
f
2g sin θ
( 56 m/s ) 2
= 3.2 × 10 2 m
ÊÁ
ˆ˜
2
( 2 ) ÁÁÁ 9.81 m/s ˜˜˜ ( sin 30.0° )
Ë
¯
PTS:
ANS:
ANS:
ANS:
1
B
D
C
PTS:
PTS:
1
1
DIF:
DIF:
I
I
OBJ:
OBJ:
5-1.2
7-4.1
1
1
1
DIF:
DIF:
DIF:
II
I
I
OBJ:
OBJ:
OBJ:
5-1.4
7-1.2
5-2.3
12 m/s 2
Given
v t = 17 m/s
r = 24 m
Solution
ac =
23.
24.
25.
PTS:
ANS:
ANS:
ANS:
vt 2
( 17 m/s ) 2
=
= 12 m/s 2
r
24 m
1
A
D
A
PTS:
PTS:
PTS:
3
ID: B
26.
ANS:
B
Given
W in = 1.00 × 10 2 J
W out = 35 J
Solution
W out
35 J
eff =
=
= 0.35 = 35%
Win
1.00 × 10 2 J
27.
PTS:
ANS:
1
D
DIF:
IIIA
OBJ:
7-4.4
1
DIF:
I
OBJ:
5-2.1
I
OBJ:
5-2.1
2.1 m/s 2
Given
v t = 2.6 m/s
r = 3.2 m
Solution
ac =
28.
29.
vt 2
( 2.6 m/s ) 2
=
= 2.1 m/s 2
r
3.2 m
PTS:
ANS:
ANS:
1
C
C
PTS:
2.4 × 10 4 N
Given
m = 2.0 × 10 3 kg
v t = 17 m/s
r = 24 m
Solution
ÊÁÁ
ˆ˜˜
3
2
ÁÁ 2.0 × 10 kg ˜˜ ( 17 m/s )
mv t 2
Ë
¯
Fc =
=
= 2.4 × 10 4 N
r
24 m
30.
PTS:
ANS:
1
D
PTS:
1
DIF:
4
Quiz 6--Work, Gravitation, Circular Motion, Torque. (60 pts available, 50 points possible) [Version Map]
MC
MC
MC
MC
MC
MC
MC
MC
MC
MC
MC
MC
MC
MC
MC
MC
MC
MC
MC
MC
MC
MC
MC
MC
MC
MC
MC
MC
MC
MC
A
B
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
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25
26
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28
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30
14
29
8
3
22
17
30
19
27
21
18
24
11
13
16
2
6
4
5
9
12
10
7
20
1
15
25
23
26
28
1