Hand back Statics Lab and go over any questions.
Finish 2nd Law video - emphasize the effect of air resistance on objects.
Modeled air resistance as knocking aside air molecules. Used hand outside car as example. The air resistance depends on two factors, the speed and the cross-sectional area. Discussed why air resistance goes up as the square of the speed (If you double the speed, you knock aside twice as many air molecules, each hitting twice as hard.)
Parachute example - same cross sectional area.
Through the air, the heavier object falls faster because it takes a greater speed to build up enough air resistance to balance the weight.
Terminal velocity occurs when the object falls fast enough so that the air resistance balances the weight.
No comments:
Post a Comment