1. A 50000-kg railroad freight car collides with a stationary caboose car. They couple together, and 31 percent of the initial kinetic energy is dissipated as heat, sound, vibrations, etc. What is the mass of the caboose?
2. A bullet with a mass of 19.80 g is fired horizontally at a block resting on a frictionless and smooth table top. The bullet embeds itself in the 0.35 kg block. The bullet and block move at 2.51m/s. Find out the speed of the bullet before it hit the block and the amount of kinetic energy is lost in the collision for the entire system bullet block?