# Gravitation Worksheet-12

Gravitation Worksheet-12

1. A mug full of water appears light as long as it is under water in the bucket than when it is outside water. Why?

1. What happens to the buoyant force as more and more volume of a solid object is immersed in a liquid? When does the buoyant force become maximum?

1. Why do we feel light on our feet when standing in a swimming pool with water up to our armpits ?

1. Explain why, big boulders can be moved easily by flood.

1. An iron nail sinks in water but it floats in mercury. Why ?

1. Explain why, a piece of glass sinks in water but it floats in mercury.

1. Steel sinks in water but a steel boat floats. Why ?

1. Explain why, school bags are provided with wide straps to carry them.

1. Why does a sharp knife cut objects more effectively than a blunt knife ?

1. Explain why, wooden (or concrete) sleepers are kept below the railway line.

1. Explain why, a wide steel belt is provided over the wheels of an army tank.

1. Explain why, the tip of a sewing needle is sharp.

1. When is the pressure on the ground  more when a man is walking or when a man is standing? Explain.

1. Explain why, snow shoes stop you from sinking into soft snow.

1. Explain why, when a person stands on a cushion, the depression is much more than when he lies down on it.

1. Use your ideas about pressure to explain why it is easier to walk on soft sand if you have flat shoes rather than shoes with sharp heels.

1. Explain why, a nail has a pointed tip.

1. Explain why, buildings and dams have wide foundations.

1. Why does a ship made of iron and steel float in water whereas a small piece of iron sinks in it?

1. Why do camels have large flat feet?