Force, work energy and power – equations
Work done = Energy transformed = Force x displacement =
FscosA
(This is an example of two vectors being multiplied together to give a
scalar)
Fire-fighter sliding down a pole
mgh – ½mv2 = Fh
Climber sliding down a rope
mgh – ½mv2 = Fh
Parachutist
mgh – ½mv2 = Fh
with the parachute open the parachutist
falls at their terminal velocity and so:
At terminal velocity: Drag force (F) = mg
Skier on a
slope
mgh – ½mv2 = Fs = Fsin A
where A
is the angle of the slope with the horizontal
Car braking to a
stop
½mv2 = Fs
Power = Work done/Time taken = Fs/t = Fv
Useful summary of similar
equations involving Force
Impulse = Ft = Force x time
Work = Fs = Force x displacement
Power = Fv = Force x velocity
A VERSION IN WORD IS AVAILABLE ON THE SCHOOLPHYSICS USB
