3.3 Work, Energy and Power Flashcards
Define work done (2)
Force x distance moved in direction of force
Energy transferred
What is energy?
The capacity to do work
What is the principle of conservation of energy?
The total energy of a closed system remains constant; energy can never be created or destroyed, but it can be transferred from one form to another
What is kinetic energy? (2)
1/2 x mass x velocity^2
The energy due to the movement of an object
What is gravitational potential energy? (2)
mass x g x vertical height difference (in a uniform gravitational field)
The energy due to the position of an object in the Earth’s gravitational field
When does ΔGPE = ΔKE?
When no resistive forces are involved
What is power? (2)
Work done / time (or force x velocity)
The rate of work done
How is efficiency calculated?
(Useful output energy / total input energy) x 100
