S.2 ASSIGNMENT ON WORK ENERGY AND POWER

1.     (a)       Define the following terms.

(i)        Work.                                    

(ii)       Power.           

            (b)       State and define the SI units of the terms you have defined above.

(c)        A crane lifts a load of 3500 N through a vertical height of 5 m in 5 second.

Calculate:     (i)        the work done.           

(ii)       the power developed by the crane.

2.     (a)       Define the term energy and state the SI unit for measuring it.

(b)       Distinguish between potential energy and kinetic energy.

(c)        A block of mass 2 kg falls freely from rest through a distance of 3m. Find the kinetic energy of the block.

3.      (a)       Define a joule.                    

            (b)       Describe briefly how you can measure your power.

(c)       A boy of mass 45 kg runs up a flight of 60 steps in 5 seconds. If each step is 12 cm.

Calculate:     (i)        the work done against gravity by the boy.

                                                (ii)       the power developed by the boy.