A 53.0 kg boy and his 41.0 kg sister, both wearing roller blades face each other at rest. The girl pushes the boy hard, sending him backward with a velocity 3.00 m/s toward the west. Ignore friction.

Question

(a) Describe the subsequent motion of the girl, and then check it against the posted solution after the assignment is due. Although this will not count directly on your grade, it will be good preparation for the test. How much chemical energy is converted into mechanical energy in the girl's muscles?

Answer 1

(a) Use conservation of momentum.

The mechanical energy converted by the girl equals the increase in the combined kinetic energy of both