3.4.1.7 - Work, Energy And Power Flashcards
What is 1 joule?
Is equal to the energy to raise a 1N weight through a height of 1 metre.
What is work done?
The energy transferred by means of a force.
Work done =
Force x distance moved in direction of the force
Underneath what two graphs is work done?
- Under a force extension graph (1/2 FΔe)
- Under a force displacement graph (F x Δs)
What is the rate of doing work equal to?
The rate of energy transfer.
Power =
Work done / time
Energy transferred / time
Force x velocity
Efficiency =
Useful energy transferred / total energy transferred
What is the efficiency equation in terms of power?
Output power of a machine / input power of a machine
What do you need to remember about work done?
Work is the energy that has been changed from one form to another, not necessarily the total energy.
What does the work done equation assume?
That the direction of force is the same as the direction of movement.
What is the equation for work done when an angle is involved?
Fcos0 x Δs
