IB SL Physics Unit 2.3: Mechanics - Work, energy, and power

energy

energy

the ability to do work or cause change

work

force * displacement, measured in Joules

Joules

N*m = kgm²/s²

Kinetic

energy of motion (.5mu²)

potential

energy due to position or composition (chemical, gravitational, elastic, electric, nuclear, magnetic)

both

internal or mechanical energy

power

energy/time = J/s = Watt (W)

Hooke’s Law

F=-kx

Energy final

energy initial is always equal to

efficiency

useful energy/total energy = useful power/total power = 34% KE

combustion engine

CPE; KEf +TEf + sound

dam energy conversions

GPEw →KEw→KEt→EE (electrical energy)

momentum

mass in motion

m*v

p (momentum) =

impulse

an object’s change in momentum

Ft

J (impulse) =

conserved

momentum is __________ in every collision

inelastic collision

KE is not conserved (real life collisions)

elastic collision

KE is conserved