eguruchela


Work


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


12


Example


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

9


10


11


Power


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


13


Kinetic Energy



14


Kinetic Energy Of A Massive Rotating Body



30


16


Work Energy Principle



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


17


Potential Energy



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


15


19


Conservation of Mechanical Energy



20


Conservation Of Energy



21