Solve the following examples:
If the energy of a ball falling from a height of 10 metres is reduced by `40%`, how high will it rebound?

If the energy of a ball falling from a height of 10 minutes is reduced by 40% , how high will it rebound ?

If the energy of a ball falling from a height of 20 m is reduced by 60% , how high will it rebound?

Solve the following examples / numerical problems: A metal ball of mass 5 kg falls from a height of 490 m. How much time will it take to reach the ground ?

Solve the following examples: How many molecules of water are there in 1 g of wate (H_2 O) ?

Solve the following examples: If the energy required to move a body of mass 1 kg from the ground level to a certain height is 49 J, find the height.

Solve the following examples / numerical problems: An iron ball of mass 3 kg is released from a height of 125 m and falls freely to the ground. Assuming that the value of g is 10 m/s^2, calculate (a) the time taken by the ball to reach the ground (b) the velocity of the ball on reaching the ground.

Solve the following examples: A body of mass 1 kg has kinetic energy 2 J. Find the velocity of the body.

Solve the following examples: Calculate the following : Mass of 2.4 times 10^(24) atoms of iron.

Solve the following examples: Find the mass of water lifted by a pump of power 0.5 hp to a height of 5m in 98 seconds.