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P1.6 Energy Dissipation - Coggle Diagram
P1.6 Energy Dissipation
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Friction
Example 1 - When a bikes brakes, friction acts between the brake blocks and wheels. Energy is wasted as thermal energy.
Example 2 - Friction acts between a drill and a wood bit as it bores into the wood. Energy is transferred form electric to thermal energy stores.
Friction at work
As you exercise in a running machine, energy is transferred to the thermal energy store of your muscles (you get hot) AND to the thermal energy store of the machine to overcome friction in the running machine below.
Spreading out
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Useful energy is eventually transferred into the surroundings to.
Example - F1 cars, they attempt to increase the thermal energy stores of the tires by heating them up and the track which increases grip.
The more that energy spreads out, the less useful it becomes
Key points
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Wasted energy is eventually transferred to the surroundings, which become warmer.
As energy dissipates, it gets less and less useful.
Energy Transferred by an electric fan heater = useful energy: warms air and surrounding objects
wasted energy: sound / KE of air
Energy transferred by a TV =
useful energy: light and sound
wasted energy: heat
Energy transferred by an electic kettle =
useful energy: boils water
water energy: heat lost through surfaces, sound
Energy transferred by headphones =
useful energy: sound
wasted energy: heat loss