A boy of mass 50 kg runs up a staricase of 45 steps in 9 s. If the height of each step is 15 cm, find his power.

A man whose mass is 50 kg climbs up 30 steps of a stair in 30 s. If each step is 20 cm high, calculate the power used in climbing stairs.

A bomb of mass 9 kg explodes into pieces of masses 3 kg and 6 kg. The velocity of 3 kg mass is 16 m/s. Find the kinetic energy associated with the 6 kg mass.

A boy of mass 50 kg running at 5ms^-1 jumping a trolly of 20 kg travelling in the same direction 1.5 ms^-1 . Find their common velocity.

A boy of mass 18 kg is running with a speed of 12 km/h. Find the kinetic energy possessed by the boy.

If a man lifts a load up with the help of rope such that it raises the load of mass 50 kg to a height of 20 m in 100 seconds. Find the power of man. (Take g = 10ms^-2 )

A bullet of mass 40 g hits a mud wall with speed 400 m s^-1 . The bullet stops after penetrating 50 cm inside the wall. Find the average resistive force exerted by the wall on the bullets.

A 10 kW drilling machine is used to drill a bore in a small aluminium block of mass 8.0 kg. How much is the rise in temperature of the block in 2.5 minutes, assuming 50% of power is used up in heating the machine itself or lost to the surroundings. Specific heat of aluminium = 0.91 J g^-1 ^@C^-1