Chapter 2, Problem 41A

Why can’t the strong man pull hard enough to make the chain perfectly straight?

To determine

To explain: The reason due to which a man is unable to pull the chain hard enough to make it perfectly straight.

Explanation of Solution

Introduction:

At equilibrium position or condition, net force exerted on an object is zero.

Consider the given situation diagram is shown below.

A strong man is pulling a chain in X-direction, while force due to gravity (weight of book) exerted on chain in Y-direction. As the force applied by man increases, chain becomes straighter. So, the net force exerted in X-direction becomes zero but, due to weight of book net force in Y-direction does not become zero. Due to this chain slightly bents downwards.

Conclusion:

A strong man cannot make chain perfectly straight because gravitational pull on chain is in downward direction.