Question

it is difficult to walk on sand surface​

Answer 1

Answer:

sand is soft and loosely held and marshy soil is wet and slippery which reduce the friction so,When we walk on the sand we push the sand with our feet but the sand yields, i.e., it does not react back with the same force because of less friction. That is why it is difficult to walk on sand or marshy land.

Answer 2

Answer:

As we press against the sandy ground in the backward direction, the sand gets pushed away and as a result we get very small reaction from the ground, making it difficult to walk.