A rock attached to a string swings in a vertical circle.Which free body diagram could correctly describe the force(s)on the rock when it is at the lowest point?

Question

Quizplus · Accepted Answer

At the lowest point of the swing, the rock is moving with its maximum speed and is experiencing the maximum tension force from the string. The weight of the rock is still acting downwards. Therefore, the free body diagram should include the weight acting downwards and the tension force acting upwards. Choice B shows this correctly.

A Rock Attached to a String Swings in a Vertical