A hockey goalie is standing on ice. Another player fires a puck (m = 0.17kg) at the goalie with a velocity of 43.1m / s, 

(a) If the goalie catches the puck with his glove in a time of 2.61*10^ -3 s what is the magnitude of the average force exerted on the goalie by the puck ? 

(b) Instead of catching the puck, the goalie slaps it with his stick and returns the puck straight back to the player with a velocity of -43.1 m / s The puck and stick are in contact for a time of 2.61*10^ -3 s . Now, what is the magnitude of the average force exerted on the goalie by the puck?