question_answer 35)

                  A body is falling freely under the action of gravity alone in vacuum. Which of the following quantities remain constant during the fall?                 (a) Kinetic energy.                 (b) Potential energy.                 (c) Total mechanical energy.                 (d) Total linear momentum.                

Answer:

                  (c) During free fall, K.E and momentum increase and P.E decrease. But K.E. + P.E. mechanical energy remains the same.