A railway engine of mass 2 tons moving at a speed of 72 km `h^(-1)` collides with a wagon at rest. After collision both have a common velocity of 36 km `h^(-1)`. Find the mass of the wagon. (1 ton = 1000 kg)

A ball of mass 100g moving at a speed of 12 m s^(-1) strikes another ball of mass 200 g at rest. After the collision both the balls move with a common velocity. Find the common velocity.

Ramu saw in a NEWS channel that a goods train of mass 200 metric ton moving with a velocity of 72 km h^(-1) collides with a passenger train of mass 300 metric ton with a velocity of 54 km h^(-1) coming in the opposite direction on the same track and both the trains move together after collision. He calculates their common velocity. Find what could be his answer.

What is the kinetic energy of a 10kg mass moving at a speed of 30 km h^(-1) in calorie?

A ball of mass 100g moving at a speed of 12 m s^(-1) strikes another ball of mass 200 g at rest. After the collision both the balls stick to each other and move with a common velocity. Find the common velocity.

A railway carriage of mass 9000kg moving with a speed of 36kmh^(-1) collides with a stationary carriage of the same mass. After the collision, the two get coupled and move together. What is this common speed ? What type of collision is this?