When one store ofenergy is transferred to another, not all of it is useful, so there is wasted energy.
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What are some examples of wasted energy?
With wires, heat is sometimes let off, and as heat isn't needed for the wire to work, it is a wasted energy.
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What is the equation for the efficiency of energy transfer?
efficiency of energy transfer = useful energy output/total energy output x 100
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Perpetual machines can continue moving forever without ever stopping. Why are perpetual motion machines impossible?
In every energy transfer process, some energy is wasted. Toasters giving off light energy is an example of this. This waste of energy means that the efficiency of energy transfer is less than 100%. This means that the machine would eventually stop.
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What are 3 ways that you can decrease the amount your house cools down?
Thicker walls, double glazing windows, loft insulation, fit carpets, cavity wall insulation and walls made from low conductivity materials.
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What is a way to reduce frictional force?
Lubricants can reduce the friction between the surfaces of objects that are rubbing together. Lubricants are normally liquids.
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What is the equation for work done?
ower (watts, W) = work done (joules, J) ÷ time (seconds, t
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What is the equation for energy transfer?
Power (watts, W) = energy transferred (joules, J) ÷ time (seconds, t)
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When a current flows through a light bulb, it emits 30 J light energy in 2 seconds, What is the power of the bulb?
What happens if you increase the mass of an object?
It increases its gravitational potential energy.
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T/F There always has to be energy wasted
True
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A toy car has a spring launch system. The toy is pulled back to load the spring, then released. The car then travels at speed along its track. What is the correct energy transfer for this process, assuming no energy is lost?
Elastic potential energy to kinetic energy
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Other cards in this set
Card 2
Front
What are some examples of wasted energy?
Back
With wires, heat is sometimes let off, and as heat isn't needed for the wire to work, it is a wasted energy.
Card 3
Front
What is the equation for the efficiency of energy transfer?
Back
Card 4
Front
Perpetual machines can continue moving forever without ever stopping. Why are perpetual motion machines impossible?
Back
Card 5
Front
What are 3 ways that you can decrease the amount your house cools down?
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