Why is it difficult to walk on sand?

Why is it difficult to walk on a slippery road?

Why is it dificult to walk on solid ice?

Why is it more difficult to walk properly on a well-polished floor ?

Give reasons for the following statements: (a) Railway tracks are laid on large sized wooden sleepers. (b) It is difficult to walk on and. (c) Walking bare footed on a pebbled path is painful.

Why is it difficult to kae vaccines for influenza?

Why is it difficult to climb up a greasy pole ?

Why is it difficult to pull out the hush of a coconut ?