Energy
- Measure of a system's capacity to do work
Work
- Transfer and transformation of energy between one body and another
- Work done by a force on a body is the product of the force and its displacement in the direction of the force
W = Fs
- Work done = area under F - S graph
- Work done by a gas = p (Δ V)
Mechanical Energy
- Sum of kinetic and potential energy
Kinetic Energy
- Measure of energy possessed by the body by virtue of its motion
- KE = 1/2 mv^2
Potential Energy
- Amount of work that was done on a body to gain that position
- Types: (i) Gravitational Potential Energy
- Measure of energy possessed by the body by virtue of its position in a gravitational field
- GPE = mgh
(ii) Elastic Potential Energy
- Elastic potential energy = 1/2kx^2
Relationship between field force and potential energu
- F = - ( dU / dr)
Principle of Conservation of Energy
- Energy can be converted from one form to another but cannot be created or destroyed
- Energy gain = Energy lost
Power
- rate at which work is done
- Instantaneous Power, P = dW / dt
- Average power, <P> =ΔW / Δt
Relationship between Power, Force and Velocity
- P = Fv
Efficiency
- Useful energy power / Total energy input
- Measure of a system's capacity to do work
Work
- Transfer and transformation of energy between one body and another
- Work done by a force on a body is the product of the force and its displacement in the direction of the force
W = Fs
- Work done = area under F - S graph
- Work done by a gas = p (Δ V)
Mechanical Energy
- Sum of kinetic and potential energy
Kinetic Energy
- Measure of energy possessed by the body by virtue of its motion
- KE = 1/2 mv^2
Potential Energy
- Amount of work that was done on a body to gain that position
- Types: (i) Gravitational Potential Energy
- Measure of energy possessed by the body by virtue of its position in a gravitational field
- GPE = mgh
(ii) Elastic Potential Energy
- Elastic potential energy = 1/2kx^2
Relationship between field force and potential energu
- F = - ( dU / dr)
Principle of Conservation of Energy
- Energy can be converted from one form to another but cannot be created or destroyed
- Energy gain = Energy lost
Power
- rate at which work is done
- Instantaneous Power, P = dW / dt
- Average power, <P> =ΔW / Δt
Relationship between Power, Force and Velocity
- P = Fv
Efficiency
- Useful energy power / Total energy input