Question

A boy throws a rubber ball vertically upwards. What type of work, positive or negative is done: 

a) by the force applied by the boy? 

b) by the gravitational force of earth?

Answer 1

a) The force applied by the boy is a positive work as it is in the direction of motion of the body. 

b) The work done by the gravitational force of the earth is negative as it is against the direction of motion of the body.