Why do tools meant for cutting always have sharp edges? 

A block of wood having a mass $15 \mathrm{kg}$ and dimensions $40\mathrm{cm} \times 30\mathrm{cm} \times 20 \mathrm{cm}$ is kept on a table-top, It is made to lie on the table-top in three ways with its sides of dimensions

(a) $40 \mathrm{cm} \times 30 \mathrm{cm}$

(b) $30 \mathrm{cm} \times 20 \mathrm{cm}$

(c) $20 \mathrm{cm} \times 40 \mathrm{cm}$
 

The pressure exerted by the wooden block on the table-top will be

Sharp-edged tools exert less pressure on a surface.

When the force acting on the area is doubled, while the area is halved.

When the force acting on an area is doubled.

A balloon can be easily burst with a spoon than a needle.

When an area on which a force acting is halved.

Pointed screwdrivers exert more pressure on a surface.