Energy in a system can be changed, in particular by mechanical work. It cannot be created or destroyed but it can be transferred, dissipated or stored in different ways.
What is the name of the energy stored by a moving object?
Elastic potential energy
Gravitational potential energy
Which of these has a chemical energy store?
A stretched catapult
A catapult stored in a cupboard
What is the main energy transfer for an apple falling from a tree?
Kinetic energy → elastic potential energy
Chemical energy → gravitational potential energy
Gravitational potential energy → kinetic energy
What is the main energy transfer for a long distance runner?
Kinetic energy → chemical energy
Chemical energy → kinetic energy
Which change can happen in a closed system?
Total energy in the system increases
Energy leaves the system, reducing the total in the system
Energy transfers from one store to another
If 4,000 J of energy is transferred and 2,500 J is usefully stored, how much energy is wasted?
What happens to 'dissipated' energy?
It is transferred to useful stores
It disappears from the system
It increases the internal energy store (temperature) of the surroundings
What is the gravitational potential energy stored in a 60 kg child sitting at the top of a 2 m high slide? (g = 10 N/kg)
A girl pushes a crate four metres with a force of 230 N. How much work does she
A 4 kg ball has 50 J of kinetic energy. How fast is it moving? - Higher