An ice skater of mass 82 kilograms stands at rest in her skates on the ice rink. Someone throws a 5-kg ball at her at a
speed of 174 m/s and she catches it. At what speed will she
(and the ball) slide backwards? m/s

Aheavy boy and a lightweight girl are balanced on a massless seesaw. the boy moves backward, increasing his distance from the pivot point. what happens to the seesaw? it is impossible to predict without knowing additional information. the side the boy is sitting on will tilt downward. the side the girl is sitting on will tilt downward. nothing; the seesaw will remain balanced.