GCSE-Work, Power and Energy Flashcards
The Principle of Conservation of Energy states that energy cannot ever …
be created or destroyed.
The Principle of Conservation of Energy states that energy can …
change from one form to another.
The work done on an object equals …
the energy gained by the object.
The work done by an object equals …
the energy lost by the object.
Work is done when …
a force is applied AND the point of application of the force moves.
Work equation
Work done = Force x distance moved in the direction of the force.
W = F x d
The unit for work
Joule (J) equivalent to Newton-metre (Nm)
What is meant by Power?
Power is the rate at which work is done or energy is transferred.
The equation for power
Power = Work done / Time taken
P = W / t
The unit for power
The Watt (W) equivalent to the Joule per second (J/s)
Equation for Gravitational Potential Energy
G.P.E. = mgh
(m is mass in kg, g is acceleration due to gravity, h is the height through which the object is raised.)
Equation for kinetic energy
K.E. = 1/2 mv^2
m is mass and v is velocity
Equation for efficiency
Efficiency = Useful Energy Output / Total Energy Input
How to calculate percentage efficiency
Use the efficiency equation and multiply by 100.
