Use the figure to answer the next question. A light rope runs through two frictionless pulleys of negligible mass. A mass, m, is hung from one of the pulleys and a force, F is applied to one end of the rope so that the mass moves at a constant speed.
-If the force is applied over a distance, d, the distance the mass moves is
A) 0
B) d
C) d
D) d
E) 2d

Question

Use the figure to answer the next question. A light rope runs through two frictionless pulleys of negligible mass. A mass, m, is hung from one of the pulleys and a force, F is applied to one end of the rope so that the mass moves at a constant speed. 
-If the force is applied over a distance, d, the distance the mass moves is
A) 0 
B) d 
C) d 
D) d 
E) 2d

Quizplus · Accepted Answer

Since the mass is moving at a constant speed, the tension in the rope must be equal to the force being applied. From the figure, we can see that the tension is equal to 2F. Therefore, the force being applied is F and the tension in the rope is 2F. Since the rope is moving through two pulleys, the distance the mass moves is twice the distance the force is applied over, which is 2d. Therefore, the correct answer is (C).

Use the Figure to Answer the Next Question