Question

An uniform chain of mass m and length l hangs by a thread and touches the surface of a table by its lower end. The thread is cut at time t = 0. Which of the following graph best represents the relation between force F exerted by table on the chain with time t. (Assume the fallen part immediately comes to rest after collision with table and do not form heap):

Answer 1

Correct option (C)

Explanation:

Fnet = Fdynamic + Fstatic

At any time t when x length is on the table then :

Fstatic = xλg

all the chain will be on table so

Fnet = 0 + mg (since At this position Fdyn = 0) So the correct graph is represented by option (3)