PHY221 Ch9: Work and PE

1. Recall main points: • Wnon-conservative=Emechanical

• Force from potential energy: 2. Discussion and examples• Foundation: work energy theorem: W=K• Example of use of both energy and NII: Rollercoaster

PHY221 Ch9: Work and PE1.

Mai

n Po

ints

Wnon-conservative=Emechanical

Proof:

Force from PE :

Proof:

PHY221 Ch9: Work and PE2.

Dis

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Problem: Start at top (y=h) at v =0. Loop-the-loop of radius R from ground; find max R for not falling off car w/out seatbelt.

Problem: Block down frictionless incline of height h into surface with kinetic friction mk. Distance d to stop block.

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