1. Train A, of mass 10 kg, is moving right at speed of 5 m/s from the top of a hill on the left with height 2 m. At the same time, train B, of mass 2x104 kg, is moving left at a speed of 10 m/s from the top of a hill on the right, with height 1 m. Both trains go downhill, collide in the valley between both hills, then their lock mechanisms engage, and both trains move together after the collision. Ignore friction. a. Calculate the initial mechanical energy of train A at the top of the hill. b. Calculate the initial mechanical energy of train B at the top of the hill. c. Calculate the velocity of train A when it reaches the valley, before the collision. d. Calculate the velocity of train B when it reaches the valley, before the collision. e. Calculate the velocity of both trains an instant after the collision. 2 ha VA T h