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.

    • 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