ALL NUMERICALS OF WORK,POWER AND ENERGY
Q.2. A 2000kg car traveling at 20m/s comes to rest on a level ground in a distance 100m. How large is the average frictional force tending to stop it?
Q.3. A 100kg man is in car traveling at 20m/s.
(a) Find his kinetic energy.
(b) The car strikes a concrete wall and comes to rest after the front of the car has collapsed 1m. The man is wearing a seat belt and harness. What is the average force exerted by the belt and harness during the crash?
Q.4. When an object is thrown upward, it rises to a height ‘h’. How high is the object, in terms of ‘h’ when it has lost one third of its original kinetic.
Q.5. A pump is needed to lift water through a height 2.5m at the rate of 500g/min. What must the minimum horse power of the pump be?
Q.8. A rocket of mass 0.2kg is launched from rest. It reaches a point “p” lying at a height 30.0m above the surface of the earth from the starting point. In the process + 425J of work is done on the rocket by the burning chemical propellant. Ignoring air resistance and the amount of mass lost due to the burning propellant. Find the speed “Vf” of the rocket at the point “p”