A chain of length L is placed on a horizontal surface as shown in figure At any instant x is the length of chain on rough surface and the remaining portion lies on smooth surface limitlly ` x= 0` A horizontal force p is applied to the chain (as shown in figure) in the duration from `x = 0 to x = L` For chain to move with constant speed

Options

A. the magnitude of P should increase with time
B. the magnitude of P should increase with time
C. the magnitude of P should increases first and then decrease with time
D. the magnitude of P should decreases first and then decrease with time

Answer

A

Explanation

For chain to move with constant speed P needs to be equal to frictional force on the chain. As the length of chain on the rough surface increases. Hence the friction force `f_(k)=mu_(k)N`increases. Hence A is correct choice.