1.4 Energy concepts Flashcards
Work, W
Work done by a force is the product of the magnitude of the force and the distance moved in the direction of the force.( W.D. = Fxcos θ )
Unit: J
Principle of conservation of energy
Energy cannot be created or destroyed, only transferred from one form to another. Energy is a scalar.
Potential energy, Ep
This is energy possessed by an object by virtue of its position. (in a gravitational field) Ep = mgh Unit: J
Kinetic energy, Ek
This is energy possessed by an object by virtue of its motion. Ek = 1⁄2mv2 Unit: J
Elastic potential
energy
This is the energy possessed by an object when it has been deformed due to forces acting on it.
Eelastic = 1⁄2 Fx or 1⁄2 kx2 Unit: J
Energy
The energy of a body or system is the amount of work it can do. Unit: J
Power, P
This is the work done per second, or energy transferred per second. Unit: W [= J s-1]