P1 Flashcards
Conservation of energy
Energy is not created or destroyed but merely changes forms
What is work
Work is done when an object is moved by a force
What does energy transferred equal
Work done
How do you find the work done by a force when it causes displacment ?
Work done, W = force applied, F x distance moved along the line of the force, s
Whats the equation for gravitational potential energy store
G.P.E = mass, m x gravity, g x change in height, H
How to find the kinetic energy store of an object
Kinetic energy, Ek (joules, J) = 1/2 x mass, m (kg) x speed, v2 (m/s)2
How to find the elastic potential energy
E.P.E, Ee (joules J) = 1/2 x string constant, k (N/m) x extenstion2, e2 (m2)
Useful energy
Energy transferred to where it is wanted in the way that is wanted
Wasted energy
Energy that is not usefully transferred
Input energy
Energy that is supplied to the device
How to calculate efficiency
Efficience = usefyll output energy transferred by the device (J)/total energy to the device (J) x 100
What is power ?
The rate at which energy is transferred
Measured in watts W
1W = 1J
Whats the equation for power ?
Power, P = Energy (J) / Time (s)
