Reducing Energy Waste Methods

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Questions and Answers

Which formula represents the calculation for power?

  • Power = mass × specific heat capacity × temperature change
  • Power = energy transferred + work done
  • Power = energy transferred ÷ time (correct)
  • Power = mass × specific heat capacity

In the context of energy transfers, what happens to energy?

  • Energy can be created or destroyed.
  • Energy can be transferred usefully, stored, or dissipated but not created or destroyed. (correct)
  • Energy can only be stored.
  • Energy cannot be stored.

What unit is power measured in?

  • Joules per kilogram per degree Celsius
  • Seconds
  • Joules
  • Watts (correct)

Why is energy often described as being 'wasted'?

<p>Because in all system changes energy is dissipated, stored in less useful ways. (C)</p> Signup and view all the answers

What does a higher power rating imply in a motor?

<p>The motor can do the same work faster. (B)</p> Signup and view all the answers

How would better thermal insulation contribute to energy efficiency?

<p>By reducing the need for energy transfer. (A)</p> Signup and view all the answers

What is the formula to calculate efficiency of a system?

<p>Efficiency = useful power output / total power input (B)</p> Signup and view all the answers

Which of the following materials would allow heat to travel through it more easily?

<p>Plastic with high thermal conductivity (C)</p> Signup and view all the answers

How can the efficiency of a machine be increased according to the text?

<p>By reducing waste output like proper lubrication (A)</p> Signup and view all the answers

Which energy source is classified as non-renewable?

<p>Coal (B)</p> Signup and view all the answers

What effect does double glazing have in terms of energy transfer according to the text?

<p>Decreases useful thermal energy loss (D)</p> Signup and view all the answers

How does reducing friction by proper lubrication impact energy loss in a motor?

<p>Decreases energy lost as heat (A)</p> Signup and view all the answers

What is the formula to calculate kinetic energy?

<p>$Ek = \frac{1}{2}mv^2$ (D)</p> Signup and view all the answers

When a moving ball hits a wall, which type of energy transfer occurs?

<p>Kinetic to sound energy (D)</p> Signup and view all the answers

What is the formula for elastic potential energy stored in a spring?

<p>$Ee = ke^2$ (A)</p> Signup and view all the answers

What does the specific heat capacity measure?

<p>Energy required to raise temperature per unit mass (D)</p> Signup and view all the answers

What happens to kinetic energy when a vehicle slows down due to friction?

<p>It transforms into thermal energy (C)</p> Signup and view all the answers

In the context of energy transfers, what is one way to reduce energy waste?

<p>Increasing system efficiency (C)</p> Signup and view all the answers

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