In an experiment, a block of mass 2m is released from rest down the 4.2 m high curve, as shown. The block collides with a second block of mass 3m at the bottom of the curve. Assuming a perfectly elastic collision, determine the rebound height of the 2m block.

Two marbles collide head-on in an elastic collision. Marble A has a mass of 14 g and is initially moving to the right at 2.5 m/s, while Marble B has a mass of 12 g and is initially moving to the left at 3.2 m/s. Assume that motion to the right is considered positive, and motion to the left is considered negative. What will be the final speed and direction of each marble after the collision, assuming that the collision is perfectly elastic?

A 3.5 kg sphere moving at 3.2 m/s collides with a second sphere of equal mass initially at rest. The direction of the first sphere changes by 20 degrees, and its new speed is 2.5 m/s. Express the lost mechanical energy as a percentage of the system's mechanical energy before the collision.

Two hockey pucks slide on a frictionless ice surface towards each other. The first puck, with a mass of 0.15 kg, moves to the right at a speed of 5.0 m/s, while the second puck, having a mass of 0.20 kg, moves to the left at 3.0 m/s. Assuming the collision between the pucks is perfectly elastic, calculate the final velocities of both pucks after the collision. Consider motion to the right to be in the positive direction.