A hockey puck with a weight of 0.50 lb is sliding freely across a section of very smooth (frictionless) horizontal ice.
(a) When it is sliding freely, how does the upward force of the ice on the puck (the normal force) compare with the upward force when the puck is sitting permanently at rest: (1) The upward force is greater when the puck is sliding; (2) the upward force is less when it is sliding; (3) the upward force is the same in both situations?
(b) Calculate the upward force on the puck in both situations.