Question

A boy of mass M is applying a horizontal force to slide a box of mass M' on a rough horizontal surface. the coefficient of friction between shoes of the boy and the floor is µ and that between the box and the floor is µ'. In which of the following cases it is certainly not possible to slide the box?

(a) µ<µ', Mµ', M
(b) µ<µ', M>M' (d) µ>µ', M>M'

Answer 1

Answer  ⇒ Option (d). µ>µ', M >M'

Explanation ⇒  Let us take an help of the mathematical expression to derive the answer.

The Force of the Friction between the Mass M and the Horizontal Surface =  µMg

Now, The Force of the Friction to between box and surface = µ'M'g

For the object to be slides, the

µMg ≥ µ'M'g

⇒ µM ≥ µ'M'

This means,   µ ≥ µ' and  M ≥ M'

Hence, Option (d). is correct.

Hope it helps.

Answer 2

Answer:

Option d is the correct