- Created by: Amy Daley 2005
- Created on: 23-03-20 10:37
Types of Energy
Energy can be created or destroyed. It can only be transferred from one store to another.
Kinetic (movement) energy store - objects are moving or speeding up
Gravitational energy store - objects are raised up and can glide
Elastic energy store - objects are squeezed or streched
Thermal energy store - objects are warmer or hotter
Chemical energy store - chemicals react such as fuel
Work Done - Force x Distance Moved
KInetic Energy - 1/2 x mass x velocity2
Gravitational potential energy - mass x gravity x height
Elastic potential energy - 1/2 x spring constant x extension2
GPE - MASS X CHANGE IN HEIGHT X GRAVITATIONAL FIELD STRENGTH
Work is the amount of energy transferred.
Mechanical work is the force(push and pull) are used to move and object meaning work is done.
1) The change in gravitational potential energy is 500 J, the height of the bar is mass= 80 kg
2) Fred pushes a lawn mower 20 metres and apllies a 15 N force what work is Fred doing?
3) What is the work done if we apply a 7 N force and we move 8 metres in the direction of the force?
4) What force is required to move 7 M if the work done is 21 J?
Answers to practise questions
1) 800= 80 x 10 800 ÷ (80 x10) = 1m Gpe = 800 J Kinetic energy is 400 J
2) 20 x 15 = 300 J
Distance units = metres (M)
Work done units = Joules (J)
Force units = Newtons (N)
Store energy = energy transferred
GPE= Gravitational potential energy
M / S = Metres per second
Energy Efficeny = useful output energy (J)
total input energy (J)
Specific heat capacity = amount of energy needed to raise the temperature of 1 kg of material by 1 degrees
unit = J/kg degrees
E = MCO E= energy transferred (J) M = mass (kg) C = specific heat capacity (J/kg degrees)
O = change in temperature.
= E ÷ (M x C) / block O
= E ÷ (M x O) / block C