Friday, Dec 10, 2010

Collected RA 6.2 and redo of RA 6.1
Handed out RA 6.3 due tomorrow.

Did several examples using the energy balance equation.
Prepped the Looney Tune Lab for tomorrow.

Wrote energy balance for pushing on block with friction and solved for final velocity. Solved the equation using acceleration to get the same answer.

Showed technique of inserting the coefficient into the KE or PE terms to calculate the new KE or new PE. Very powerful and useful technique. (Ex. What happens to the stopping distance of a car if you double the speed and double the mass?
KE old = 1/2 * m*v^2
KE new = 1/2 (2m) * (2v)^2 = 8 * 1/2 * m * v^2

Handed out problem sheet on energy. Gave students time to work on the problems in class.