Explain the following — (a) It is easier to cut with a sharp knife than with a blunt one. (b) Sleepers are laid below the rails

(a) It is easier to cut with a sharp knife than with a blunt knife because in a sharp knife even a small thrust causes a great pressure at the edges and hence, cutting can be done with less effort.

(b) Sleepers are laid below the rails so that the pressure exerted by the iron nails on the ground becomes less.