Question
Question: A body of mass m is in vertical motion under the influence of gravity then...
A body of mass m is in vertical motion under the influence of gravity then
Work will be negative and kinetic energy increases during fall.
Kinetic energy decreases when body is projected up and work will be negative.
Kinetic energy increases when body is projected up and work will be positive.
Work will be positive and kinetic energy decreases during fall.
Work will be negative and kinetic energy increases during fall.
Solution
In case of vertical motion under gravity, when the body falls, force of gravity (a conservative force) is in the direction of motion of so K.E. increases but when the body is projected upward, force of gravity is opposite to motion so K.E. of body decreases. If kinetic energy of a body increases the work is taken as positive and vice versa.