Question

Give reason: (a) cutting and piercing tools are made sharp. (b) an egg sinks in fresh water but floats in highly salty water. (c) pressure is more while a man is walking than while standing.res (d) army tank rest upon a continuous chain. (e) its easy to walk on sand with flat shoes than high heels shoes. (f) railway tracks are laid on large sized concrete sleepers

Answer 1

a) Cutting and piercing tools are made sharp so that with less pressure it will be easier to cut things.

b) An egg sinks in fresh water but floats in highly salty water due to increase in buoyancy . Salty water has more buoyancy than fresh water.

c) When man walks then his one foot falls over on smaller area so more pressure is applied. But when he is standing both his feet touches the ground , so the pressure of his body falls over smaller area.

d) Army tanks are very heavy objects. They exert a great amount of pressure so there is a chance they might sink into the ground. So, to avoid this they rest on a continuous chain.

e) The heels fall under less surface area so greater pressure is applied on the ground. That's why the heels sink. But flats fall on larger surface area so it exerts less pressure on the ground.

f) Heavy trains run on the railway tracks. These trains exert a great pressure on the tracks so there is a chance that they might sink into ground. To avoid this, large sleepers are laid below the tracks so that the pressure exerted by the trains is distributed over large surface area.

Answer 2

Answer:

a) cutting and piercing tools are made sharp because the area of contact reduced so that pressure increases and cutting become easy. b) this is because of density as salty water have higher density as compare to fresh water so, egg floats on salty water but sinks in fresh water