Two objects,each of weight W,hang vertically by spring scales as shown in the figure.The pulleys and the strings attached to the objects have negligible weight,and there is no appreciable friction in the pulleys.The reading in each scale is
A) W.
B) more than W, but not quite twice as much.
C) less than W.
D) 2W.
E) more than 2W.

Question

Two objects,each of weight W,hang vertically by spring scales as shown in the figure.The pulleys and the strings attached to the objects have negligible weight,and there is no appreciable friction in the pulleys.The reading in each scale is 
A) W. 
B) more than W, but not quite twice as much. 
C) less than W. 
D) 2W. 
E) more than 2W.

Quizplus · Accepted Answer

Since the two objects are in equilibrium, the tension in each string must be equal to the weight of the object it supports. Therefore, each scale reads W, and the total force in the system is 2W. None of the other choices are consistent with a system in equilibrium.

Two Objects,each of Weight W,hang Vertically by Spring Scales as Shown