Question

A rock is suspended from a horizontal support by a string, as shown above. An identical string is attached to the bottom of the rock. A person pulls the bottom string down, starting with a small force and increasing the force slowly until one of the strings breaks. Which of the following correctly indicates which string will break and gives an accurate justification for this claim?

Answer 1

Answer: C

Explanation:

This is because the top string not only has to support the weight of the rock but also has to withstand the additional force applied by the person pulling on the bottom string. As the force on the bottom string increases, the tension in the top string also increases, and eventually, it may exceed the tensile strength of the top string, causing it to break.