An object of unknown weight is suspended as shown. The tension in rope 1 is 25 lb, and the tension in rope 2 is 31 lb. What is the weight of the suspended object?
A)36 lb
B)33 lb
C)41 lb
D)39 lb
E)56 lb

Question

An object of unknown weight is suspended as shown. The tension in rope 1 is 25 lb, and the tension in rope 2 is 31 lb. What is the weight of the suspended object? 
A)36 lb 
B)33 lb 
C)41 lb 
D)39 lb 
E)56 lb

Quizplus · Accepted Answer

The weight of the object can be found by calculating the net force acting on it, which is the difference between the tensions in the two ropes. 
Net force = Tension in rope 1 - Tension in rope 2 
= 25 lb - 31 lb 
= - 6 lb 
Since the net force is downwards, we know the weight of the object must be upwards and is equal in magnitude to the net force. 
Therefore, the weight of the suspended object is 6 lb upwards, or 39 lb downwards (since weight is a force acting downwards). 
Thus, the correct answer is D) 39 lb.

An Object of Unknown Weight Is Suspended as Shown