In: Physics
A small girl is skating around on an ice rink. Her mass is 30 kg, and her speed is 4.0 m/s. She sees a 50 kg sled at rest on the rink that was left there by a careless worker, and she decides to jump onto the sled. Assume no friction between the sled and the ice.
a. Find the child-sled system’s speed immediately after the child jumps onto the sled.
b. Find the child-sled system’s kinetic energy immediately after the child jumps onto the sled.
After coasting around for a while, she jumps off the sled in such a way that she is stationary relative to the ice.
c. Find the sled’s speed after she jumps off it.
d. Find the girl-sled system’s kinetic energy when she is at rest on the ice.
e. Is the energy greater in part (d) than it was in (b)? If so, from where did the energy come? If the energy is less in part (d) than it was in part (b), where did the energy go?