Question

Walking becomes difficult when the ground is slippery or it is covered with sand

Answer 1

It becomes little difficult to walk on the ground which is covered with the sand or which is slippery.

This is because, the Coefficient of the Friction decreases in case the ground is covered with the sand or it is slippery.

Due to the decrease in the coefficient of the Friction, the mathematical magnitude of the Friction also deceases which is turn causes the problem to us in walking and we are unable to oppose the leg and hence unable to move.

Hope it helps .