question_answer 52)

  A ball is dropped from a height of 10 m. If the energy of the ball reduces by 40% after striking the ground, how much high can the ball bounce back?

Answer:

  If the energy of the ball reduces by 40% after striking the ground, then remaining energy of the ball will be 60% of initial energy. Let initial energy of the body of mass (m) at height (h) is (mgh). According to the question, mgh' = 60% of mgh        [given, h = 10 m and ]