Energy – the ability to do work W = Fd = m a d V f 2 = V i 2 + 2a  x V f 2 - V i 2 = + 2a  x V f 2 - V i 2 = a  x 2

W = Fd = m(V f 2 - V i 2 ) 2 W = Fd = 1 m  v 2 2 Kinetic Energy – energy of motion KE = E k = 1 mv 2 2 units: kg (m/s) 2 = kg m 2 /s 2 = kg m/s 2 m = N m = Joule

Work-Energy Theorem W net =  E k Fd = KE f – KE i Fd = 1 mv 2 f - 1 mv 2 i 2 2

Gravitational Potential Energy GPE = Ug = mgh units: kg m/s 2 m = Joule

Elastic Potential Energy PE elastic = U s = ½ kx 2 k = spring constant units: N m 2 = N m m equilibrium

Mechanical Energy – sum of all kinetic energy and all types of potential energy ME = KE +  PE Law of conservation of Mechanical Energy Energy cannot be created nor destroyed, it can only changed from one form to another ME i = ME f

Law of Conservation of Energy PE + KE = PE + KE PE = KE U g = E k mgh = 1 mv 2 2