A 75-kilogram hockey player is skating across the
ice at a speed of 6.0 meters per second. What is
the magnitude of the average force required to
stop the player in 0.65 second?
(1) 120 N (3) 690 N
(2) 290 N (4) 920 N
I think it is (3) 690 N. You can use the theorem of Impulse and momentum where the impulse is equal to the change in momentum or: [tex]F \Delta t=m v_{f}-m v_{i}[/tex] (where f is for final and i for initial). So you get: [tex]F*0.65=0-(75*6)[/tex] [tex]F=692 N[/tex]
