A bullet of mass 10 g pierces through a plate A of mass 500 g and then gets embedded into a second plate B of mass 1 . 49 kg as shown in the figure. Initially the two plates A and B are at rest and move with same velocity after collision. The percentage loss in the initial kinetic energy of the bullet when it is between the plates A and B is_______. (Neglect any loss of material of the plates during the collision)

Step-by-step solution

Let us suppose that the mass of the bullet is, m = 10   g = 10 - 2   kg and M A = 1 2   kg ,     M B = 1 . 49   kg   , now the loss of kinetic energy of a bullet is, ∆ K . E . × 100 = - 1 2 m v 1 2 - 1 2 m u 2 1 2 m u 2 × 100 = - v 1 2 - u 2 u 2 × 100 ∆ K . E . × 100 = - v 1 2 u 2 - 1 × 100 for plate A conservation of momentum, m u = m v 1 + M A v ⇒ m u - v 1 = M A v for the plate, B the bullet is combined with plate, m v 1 = m + M B v no