A 5 kg ball travelling to the right at 8 m/s collides with a 3 kg ball at rest.

A 5 kg ball travelling to the right at 8 m/s collides with a 3 kg ball at rest. After the collision, the 3 kg ball is travelling to the right at 10 m/s, and the 5 kg ball is traveling to the right at 2 m/s. Is this an elastic collision?

A 6 kg ball travelling to the right at 10 m/s collides with a 4 kg ball at rest. After the collision, the 4 kg ball is travelling to the right at 9 m/s, and the 6 kg ball is traveling to the right at 4 m/s. Is this an elastic collision?