AP PROBLEM ENERGY AND MOMENTUM IN COLLISIONS

A 30 KG CHILD MOVING AT 4.0 M/S JUMPS ONTO A 50 KG SLED THAT IS INITALLY AT REST ON A LONG, FRICTIONLESS, HORIZONTAL SHEET OF ICE.

A) DETERMINE THE SPEED OF THE CHILD-SLED SYSTEM AFTER THE CHILD JUMPS ONTO THE SLED.

B) DETERMINE THE KINETIC ENERGY OF THE CHILD-SLED SYSTEM AFTER THE CHILD JUMPS ONTO THE SLED.

AFTER COASTING AT CONSTANT SPEED FOR A SHORT TIME, THE CHILD JUMPS OFF THE SLED IN SUCH A WAY THAT SHE IS AT REST WITH RESPECT TO THE ICE.

C) DETERMINE THE SPEED OF THE SLED AFTER THE CHILD JUMPS OFF OF IT.

D) DETERMINE THE KINETIC ENERGY OF THE CHILD-SLED SYSTEM WHEN THE CHILD IS AT REST ON THE ICE.

E) COMPARE THE KINETIC ENERGIES THAT WERE DETERMINED IN PARTS (B) AND (D). IF THE ENERGY IS GREATER IN (D) THAN IT IS IN (B), WHERE DID THE INCREASE COME FROM? IF THE ENERGY IS LESS IN (D) THAN IT IS IN (B), WHERE DID THE ENERGY GO?