Rotational Motion
Practice Test
1.
A mass that rotates around its own axis is a(n) __________.
a.
orbiter
b.
rigid rotating object
c.
projectile
d.
satellite
Hint
2.
In Figure 5-11, if B's magnitude is 50 N and C's is 30 N, what is the magnitude of A?
a.
58 N
b.
20 N
c.
40 N
d.
80 N
Hint
3.
If the satellite in Figure 7-10 were to remain above the same point on Earth, what would its orbital radius have to be changed to?
a.
2.2×10
11
m
b.
1.1×10
11
m
c.
1.7×10
11
m
d.
1.3×10
11
m
Hint
4.
You are riding in a boat that is traveling 15.0 m/s in still water. You move from the bow to the stern at 3.0 m/s. What is your speed relative to the water?
a.
15.3 m/s relative to the water
b.
18.0 m/s relative to the water
c.
12.0 m/s relative to the water
d.
9.0 m/s relative to the water
Hint
5.
In Figure 8-5, if
m
1
= 1.0 g,
m
2
= 5.0 g, and
r
1
= 6.0 cm, what is
r
2
?
a.
1.2 cm
b.
0.83 m
c.
0.83 cm
d.
1.2 m
Hint
6.
In Figure 8-2, if the radius of the CD is 6.0 cm and the angular velocity is 5.0 rad/s, what is the linear displacement of a point on the edge in 2.0 s?
a.
3.8 m
b.
60 m
c.
0.30 m
d.
0.60 m
Hint
7.
The acceleration of an object in uniform circular motion is called __________.
a.
equilibrium
b.
range
c.
centripetal acceleration
d.
torque
Hint
8.
The __________ is the force exerted on one surface by another when the surfaces are in relative motion.
a.
kinetic coefficient
b.
apparent weight
c.
static friction force
d.
kinetic friction force
Hint
9.
In Figure 8-3, why does applying a force as in the picture at the bottom left result in no effect?
a.
The force is applied perpendicular to the lever arm.
b.
The force is applied perpendicular to the axis of rotation.
c.
The force is applied at the axis of rotation.
d.
The force is applied parallel to the lever arm.
Hint
10.
A stone is thrown horizontally at 20 m/s from the top of a cliff 63 m high. How fast is it moving the instant before it hits the ground?
a.
29 m/s
b.
33 m/s
c.
40 m/s
d.
38 m/s
Hint
11.
A sled of mass 40.0 kg is pulled along flat, snow-covered ground. The static friction coefficient is 0.28, and the kinetic friction coefficient is 0.08. What force is needed to keep the sled moving at a constant velocity?
a.
31 N
b.
3.2 N
c.
3900 N
d.
310 N
Hint
12.
If you weigh 440.0 N on Earth's surface, how much would you weigh on the planet Mars? Mars has a mass of 6.42×10
23
kg and a radius of 3.40×10
6
m.
a.
557 N
b.
165 N
c.
235 N
d.
1.4×10
3
N
Hint
13.
Which two conditions make an object the most stable?
a.
a high center of mass and a narrow base.
b.
a high center of mass and a large base.
c.
a high center of mass and a narrow base.
d.
a low center of mass and a large base.
Hint
14.
What happens to an object when its velocity and angular velocity are zero or constant?
a.
It's in rotational equilbrium.
b.
It accelerates.
c.
It's in translational equilibrium.
d.
It's in static equilibrium.
Hint
15.
According to Newton's law of universal gravitation in the case of a planet near the Sun, which of the following would cause the attractive force to be quadrupled?
a.
quadruple the mass of the planet
b.
double the distance from the Sun
c.
quadruple the distance from the Sun
d.
square the mass of the planet
Hint
16.
In Figure 7-5, if the mass of the planet were doubled, what effect would it have on its period of orbit?
a.
The new period would be one-half of the original period.
b.
It would have no effect.
c.
The new period would be twice the original period.
d.
The new period would be one-quarter of the original period.
Hint
17.
The __________ is the height of the projectile when the vertical velocity is zero.
a.
trajectory
b.
range
c.
torque
d.
maximum height
Hint
18.
In Figure 6-7, if the mass of the hammer is 7.26 kg, its center is 0.50 m from the thrower, and it is moving at a speed of 1.5 m/s, what is the force of the chain on the thrower's hands?
a.
22 N, outward
b.
33 N, inward
c.
33 N, outward
d.
22 N, inward
Hint
19.
Which of the following situations is physically the most like that depicted in Figure 6-9a?
a.
You walk toward the rear of a forward-moving train.
b.
You step upwards on an upward-moving escalator.
c.
You slide to the right on the seat of a forward-moving bus.
d.
You jump up in an elevator that is going down.
Hint
20.
A 225-N weight has one horizontal rope exerting a force of 98.0 N on it. What are the magnitude and direction of the resultant force on the weight?
a.
2.45×10
2
N at 343°
b.
1.27×10
2
N at 315°
c.
2.45×10
1
N at 293°
d.
2.45×10
2
N at 293°
Hint
