CP3 - Conservation of energy

Diffrernet ways energy is stored 

Chemical potenial energy - energy stored in fuel, food or batteries 

Kenetic energy - engery stored in moving objects 

Heat energy - engery stored in hot objects 

Elastic potential energy - engergy stored in streached, squashed or twisted materials 

Gravational potenial energy - energy stored in objects in high positions 

Nuclear energy - energy stored in atoms 

Energy stored in a car (KE) ---energy transfered by forces during breaking ----- energy stored in hot breaks (heat energy) 

The efficiency is a way of describing how good a machine is at transfering energy into useful forms. 

For example a light bulb has 100 joules of energy. It may use 10 joules of the engery and it will waste the other 90 joules. We can show this on a sankey diagrm. We can say that it has an effenicany of 10%. 

To work this out we use this equation:

Efficiency = (usefull engery) ÷ (total energysupplied to the object) 

Energy can be transfered in differnt ways:

Conduction - vibrations are passed on between particles in a soild. 

Convection - part of fuild that is warmer than the rest rises and sets up a convection current 

Radiation - way in which engery can be transfered by using a vacuum

To help keep warm are inside our houses we can have a double layered walls; insulating in the loft; double glassed window and radaitors.

A thermal flask is very similar to this. To keep a drink warm there is a plastic stopper, glass walls with silver coating on both sides, vacuum between walls and a platic spacer at the bottom. 

Gravatinoal potenial energy (GPE) is stored energy because of its position in a high place. 

The amount of GPE stored depends on the mass of the object, the strength of gravity and how far the object has moved upwards. We can caluclate this by using the following equation:

MASS X GRAVITY X HEIGHT (M X G X H)

To work out the kenetic engery we can use this equation:

K.E. = 1/2 m v²