Qn3

a) Define the following terms as applied to mechanics 

     i) Work

    ii) Energy 

    iii) Power

b) Name the devices which are used to make the following energy conversion 

    i) Electrical energy to mechanical energy

    ii) Mechanical energy to electrical energy

c) Distinguish between potential energy and kinetic energy 

d) A block of mass 2kg falls freely from rest through a height of 20m  

    above the  ground. Find  

       i) The potential energy of the block above the ground 

       ii) The velocity with which the block hits the ground

  e) A boy of mass 50kg runs up-flight of stairs in 2 seconds. 

      If each step is 0.2m high and there are 60 steps  in the flight.

      Calculate the boy‟s power