Forces in Two Dimensions
Practice Test
1.
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.
310 N
b.
3.2 N
c.
3900 N
d.
31 N
Hint
2.
When there is no relative motion between two surfaces, the force exerted by one surface on the other is called __________.
a.
the static friction force
b.
kinetic friction
c.
the kinetic force
d.
resistance
Hint
3.
Find the magnitude of the sum of a 10-m displacement and a 5-m displacement when the angle between them is 45°.
a.
11 m
b.
7 m
c.
9 m
d.
14 m
Hint
4.
If in Figure 5-13 the skier has mass 45 kg and the slope is at 35°, what is the component of the skier's weight perpendicular to the slope?
a.
it cannot be determined with the given information
b.
440 N
c.
360 N
d.
250 N
Hint
5.
What is the magnitude of your displacement when you follow directions that tell you to walk 150.0 m north, then 25.0 m east?
a.
127 m
b.
150 m
c.
175 m
d.
152 m
Hint
6.
A 475-N trunk is sliding down a plane inclined 40.0° above the horizontal. Calculate the magnitude of the acceleration.
a.
62.9 m/s
2
b.
7.51 m/s
2
c.
6.29 m/s
d.
6.29 m/s
2
Hint
