Work


W: work done by a force (j), F: force move a object for a distance s, α: angle between F and movement direction



Example


Wp: work by gravity, h: the change in height; wms:work of friction’s force; W: work by a spring




Power


P: power (watt, W), t: time of conducting the work W(s)



Kinetic Energy




Kinetic Energy Of A Massive Rotating Body





Work Energy Principle



v1, v2: speeds of object before and after the change



Potential Energy



Ep: gravitational potential energy (j), m: mass of object (kg)




Conservation of Mechanical Energy




Conservation Of Energy