Work, Energy and Power Flashcards
What is the definition of Energy?
a measure of the capacity to do work. Unit is Joules (J)
What is the definition of work?
The energy transferred by a force (when a force moves through a distance) Unit if Joules (J)
What is the equation for Work done?
Work Done = Force x distance moved in the direction of the force
WD = F x s
Work done can be represented as the area under a force-distance graph. If graph is non-linear then the integral is taken to calculate area
What are the different equations for power? unit of measurement
Power = Work Done / Time
Power = Force x distance / time
Power = Force x velocity
Average Power = force x average velocity
Power = Energy / time
What is the definition of Power?
The rate of doing work
How can all types of energy be split up into?
Two forms:
- Kinetic energy
- Potential energy
What types of energy is involved in mechanics?
Kinetic energy - due to bodies motion
Potential energy - due to a bodies motion above a datum
Strain energy - due to energy being stored in srping etc
What is the definition of kinetic energy?
Equation?
The energy that an object possesses due to its motion
KE = 1/2 m v^2
What is the equation for potential energy?
PE = mgh
Potential energy = mass x gravitational field strength x height
What is the law of conservation of energy?
‘Energy is neither created nor destroyed, it only changes its form’
In the case of a falling body its potential energy is gravitational so therefore its kinetic energy is the same as its potential
mgh = 1/2 m v^2
What is the equation for efficiency?
useful energy out / total energy in
x100
