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 connected by a string, they must share the same tension force. Therefore, the tension in the string must be equal to the weight of each object (W), and this tension force must be balanced by the reading on each spring scale. Therefore, the reading on each spring scale is equal to W. None of the other answer choices are correct, as they all involve a tension force greater than or less than W, which would result in an unbalanced or impossible situation.

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