A crane operator lowers a 16,000 N steel ball with a downward acceleration of 3 m/s².The tension in the cable is: A)4900 N B)11,000 N C)16,000 N D)21,000 N E)48,000 N

Question

Quizplus · Accepted Answer

The tension in the cable is equal to the weight of the object being lifted minus the force required to accelerate it. 
Tension = Weight - Force 
Weight = 16,000 N (given) 
Force = mass x acceleration = 16,000 N x 3 m/s^2 = 48,000 N 
Tension = 16,000 N - 48,000 N = -32,000 N (negative tension means the cable is slack, which is not possible) 
Therefore, the tension in the cable is 16,000 N - 11,000 N = 5,000 N. Thus, the answer is B.

A Crane Operator Lowers a 16,000 N Steel Ball with a Downward