Fluid Mechanics
On what factors does the effect of thrust on a surface depend?
When is the pressure on the ground more-when a man is walking or when a man is standing? Explain.
When a man is walking, then at one time only one foot is on the ground. Due to this, the force of weight of man falls on a smaller area of the ground and produces more pressure on the ground. On the other hand, when the man is standing, then both his feet are on the ground. Due to this, the weight of the man falls on a larger area of the ground and produces lesser pressure on the ground.
On what factors does the effect of thrust on a surface depend?
Name two factors on which the pressure on a surface depends.
A sharp pin works better than a blunt pin. explain the reason.
Why is the bottom part of foundation of building made wider ?
It is easier to cut with a sharp knife than with a blunt one. explain.
Explain the following : $$ (a) $$ Sleepers are used below the rails $$ (b) $$ A tall building has wide foundations.
Why does a sharp knife cut objects more effectively than a blunt knife?
Explain why, wooden (or concrete) sleepers are kept below the railway line.
Explain why, a wide steel belt is provided over the wheels of an army tank.
Explain why, the tip of a sewing needle is sharp.