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


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


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