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 there is no appreciable friction in the pulleys, the tension in the string is the same throughout, and so each object feels a tension of W. Since each object is in static equilibrium, the reading on each scale is equal to the tension it feels, which is W. Therefore, the answer is A) W.

Two Objects, Each of Weight W, Hang Vertically by Spring