Energy (physics)
- Created by: harrietlivv
- Created on: 08-02-18 19:28
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- Energy P1
- Kinetic energy stores
- kinetic energy= 1/2xmass(kg)xspeed2(m/s)
- the greater the mass, the faster the object will go
- any moving object has kinetic energy
- energy is transferred to the object when it speeds up
- Energy is transferred away when the object slows down
- kinetic energy= 1/2xmass(kg)xspeed2(m/s)
- Gravitational potential energy
- lifting an object in a gravitational field requires work
- This causes a transfer to the g.p.e store of the raised object
- the higher the object is lifted, the more energy is transferred to this store
- G.P.E(j)=mass(kg)x Gravitational field strength(N/Kg) x height(m)
- Gravitational field strength on earth is 10
- lifting an object in a gravitational field requires work
- Elastic potential energy
- stretching or squashing of an object
- E.P.E doesn't occur when the limit of proportionality has been excceded
- E.P.E(j) = 1/2 x spring constant(N/m) x Extension2(m)
- stretching or squashing of an object
- Specific heat capacity (Required practical involved)
- The amount of energy needed to raise the temperatre of 1Kg of a substance by 1 degree C
- Some materials require more energy to heat then others
- Change in temp (j)= mass(kg) x specific heat capacity(J/Kg degree C) x temp change (C)
- Power
- rate of energy transfer or the rate of doing work
- A powerful machine transfers a lot of energy in a short amount of time
- 1 watt = 1 joule of energy transferred per second
- Power (W) = energy tranferred(j) / time (s)
- Power (W) = workdone(j) / time (s)
- rate of energy transfer or the rate of doing work
- Efficiency
- The less energy that is wasted means the product is more efficient
- Efficiency can be improved by insulation, lubrication, or stream lining depending on what the product is
- Efficiency = useful energy output / total energy input
- The percentage can be found by multiplying your answer by 100
- if the energy isn't given use this equation which involves the power outputs
- Efficiency = useful power output / total power input
- there is no such thing as a device which is 100% efficient
- The less energy that is wasted means the product is more efficient
- Kinetic energy stores
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