Consider a frictionless track as shown in Figure P6.48. A block of mass m1 = 4.35 kg is released from A. It ma

Question

Consider a frictionless track as shown in Figure P6.48. A block of mass m1 = 4.35 kg is released from A. It makes a head on elastic collision at B with a block of mass m2 = 9.00 kg that is initially at rest. Calculate the maximum height to which m1 rises after the collision.

Answer 1

You don't provide a diagram but my guess is that it is a classical conservation of energy problem combined with a fully elastic collision in which both energy and momentum are conserved.

If A is at the high point, we can make it the origin of our system so the total energy of block 1 starts out at 0.

By the time it hits block #2, it has descended a certain height h converting m1 g h of its potential energy to kinetic energy.

Since |m g h| = (1/2) m v^2, you can compute the velocity of block #1 at B.

The kinetic energy of the two blocks after the collision = the kinetic energy before, as does the momentum of the blocks before and after.

http://en.wikipedia.org/wiki/Elastic_col...

This lets you compute the new velocity of block #1 after the collision. Since you also know its height at this point, you know its new total energy and can therefore determine the maximum height to which it can rise (the height at which all its energy is potential)