question_answer

  (a) Define potential energy. (b) Give an example where potential energy is acquired by a body due to change in its shape. (c) A skier of mass 50 kg stands at A, at the top of a ski jump. He takes off from A for his jump to B. Calculate the change in his gravitational potential energy between A and B.       

Answer:

   (a) Potential Energy It is the energy possessed by a body by virtue of its position or shape.        (b) In a toy car, the wound spring possesses potential energy. When spring is released, its potential energy changes into kinetic energy due to which the toy car moves.                                      (c) Here, m = 50 kg, = 75 m,  =60 m At point A, = 50 x 10 x 75 = 37500 J At point B, = 50 x 10 x 60 =30000 J Change in PE = 37500 - 30000 = 7500 J