Author Question: When a force acts on an object from an angle other than either 0 or 180 to the direction of motion: ... (Read 71 times)

Collmarie · **on:** Jul 28, 2018

When a force acts on an object from an angle other than either 0 or 180 to the direction of motion:
a. the force is not in the direction of motion, so no work gets done.
b. the force is perpendicular to the direction of motion, so no work gets done.
c. the parallel and perpendicular component of the force both do work.
d. the parallel vector component of the force does work but the perpendicular one does not.
e. the perpendicular vector component of the force does work but the parallel one does not.

Question 2

It takes no work to hold a cheerleader in the air, as shown here. If no work is done by the cheerleaders, why do they eventually tire?
a. Because maintaining the same position for a long time is boring.
b. Their bodies expend chemical energy as their muscles function; this is hard work, but not the same kind of work that moves a mass over a distance.
c. The concept of work, as it apples in physics, does not apply to any process that involves people.
d. The arrangement is unstable and they can easily fall over.
e. The cheerleaders at the greater height have more potential energy.