Q.16) A body of mass m falls down through a height h. Obtain an expression for the work done by the force of gravity.
Q.17) A body of mass m climbs up the stairs of vertical height h.
(a) What is the work done by the body against the force of gravity ?
(b) What would have been the work done if he uses a life in climbing the same vertical height?
Q.18) Define the term energy and state its SI unit.
Q.19) What physical quantity does the electron volt (eV) measure? How is it related to the SI unit of that quantity?
Q.20) Complete the following sentences :
(a) 1 J = __________ calories.
(b) 1 kWh = __________ J
Ans : (a) 0.24 (b) 3.6 X 10^16