Wed, Dec 8, 2010

Handed back and went over Momentum Test

Started energy

Feynman's Block example

Types of Energy
Places energy can hide - for this unit, GPE = m g h, KE = 1/2 m v^2, Elastic PE = 1/2 k x^2, work = F * d where F is the component of force in the direction of motion.

Conservation of Energy and Energy Balance Equation.

Did example of lifting a 10 kg mass. First at 120 N for 2 seconds, then at 100 N for 4 seconds and then at 60 N for 1 sec to slow it down. Drew force vs time graph. Showed applied force, weight, and net force. Since net impulse is zero, there is no change in momentum and the block comes to rest. Calculated the work done and showed that it was equal to the change in gravitational potential energy.

Main idea: If you lift an object, the work you do is equal to the increase in gravitational potential energy.

Handed out RA 6.1 due tomorrow.

Prepped Roller Coaster Lab.