In the figure, what does the spring scale read? The pulleys are ideal and the strings and scale are also massless.
A) exactly 2.0 N.
B) exactly 1.0 N
C) 0.50 N
D) 0.00 N
E) more than 19.6 N

Question

In the figure, what does the spring scale read? The pulleys are ideal and the strings and scale are also massless. 
A) exactly 2.0 N. 
B) exactly 1.0 N 
C) 0.50 N 
D) 0.00 N 
E) more than 19.6 N

Quizplus · Accepted Answer

Since the strings and pulleys are massless and ideal, the tension in each string must be the same throughout the system. Thus, the tension of the string pulling up on the scale is equal in magnitude to the weight of the 1.0 kg mass. Therefore, the spring scale reads exactly 1.0 N.

In the Figure, What Does the Spring Scale Read? the Pulleys