2. Work
Work is done when a force moves a body
through a distance in direction of the force,
and is equal to the product of force and the
distance moved
W = F x s
W = F x s cos θ (*when considering angle
of the direction)
SI Unit = Joule
A JOULE is when a force of 1N moves a body
a distance of 1m.
4. Energy
Capacity to do work
Also measured in J
Principle of conservation of energy = in a
closed system the total amount of energy is
constant
Mechanical energy can be K.E or P.E
K.E = ½ mv2
P.E = F x s= mgh
5. Law of conservation of mechanical
energy
P.E + K.E = constant
P.E + K.E at point A = P.E + K.E at point B
½ mv2 = mgh
6. Power
Time rate of doing a work measured in watts
W.
= work done = F x s = F x s/t =Force x velocity
time taken t