3) Donald Trump is driving his sturdy 2200 kg car when he sees Joe Biden stopped in his 1500 kg car, and decides to ram into the back of him! He is travelling at 30 km/h on impact, and just after the collision Biden's car is seen moving directly ahead at 20 km/h. Momentum is conserved during the duration of the crash. Biden's car is crushed in at the back by the crash, but Trump's car does not suffer any damage. How much is Biden's car shortened by the accident, assuming that a constant force of 50000 N is required to crush it? You may assume that the kinetic energy lost by the cars during the collision goes into the crushing process. (Answer: 61 cm)