A very flexible chain of mass M and length l is suspended vertically in a lift so that its lower end is just touching the surface of the floor. When the upper end of the chain is released, it falls with each link coming to rest intantaneously find the force exerted by the floor of the lift on the chain at the moment when one fourth of the chain has already landed on the floor Assume the lift is moving with acceleration `g//2`

Answer

`9 Mg//8`

Explanation

Force by the floor `=(Mg)/8+Mg`
`F=(9Mg)/8`