11/10/08
Post date: Nov 09, 2008 11:58:12 PM
Bell Activity: Explain in words what the impulse-momentum theorem (F*t=delta p) means.
Time for questions, finish labs if needed
Review impulse-momentum equation and implications
If we're changing speeds (say, from a high speed to a stop) our change in momentum will be the same no matter what force or time is used to accomplish that.
Very high forces can be hazardous to our health!
These high forces occur when the time is very small. Many safety devices (especially in cars) aim to spread a stopping force over a longer period of time.
Air bags
Crumpling bumpers
Parachutes - remember, it's not the fall that kills you, it's the sudden stop at the end!
Spiderman and momentum video: http://www.youtube.com/watch?v=kuVpwjYgvgg
Conservation of Momentum
Newton's third law implies that in a collision, the total momentum will remain constant for a closed system
p initial = p final