Conservations of Energy and Power

Question 1

Can energy be destroyed?

Answer 1

ENERGY CAN NEVER BE DESTROYED

Question 2

If not destroyed, what is the rule of energy?

Answer 2

• Energy can be transferred usefully, stored or dissipated

- Energy can never be destroyed/created

Question 3

What happens if energy isn’t transferred usefully?

Answer 3

• Some energy is always dissipated when energy transfers take place.
• This is called ‘waste energy’

Question 4

What is power?

Answer 4

• The rate of ‘doing work’
  OR
• The rate of energy transferred

Question 5

What is the equation for power? (energy transferred)

Answer 5

Power = Energy transferred
————————–
time

Question 6

What is the symbol equation for power? (energy transferred)

Answer 6

P = E (J)
—-
(W) = T (s)

Question 7

What is the equation for power? (work done)

Answer 7

Power = Work done
—————–
time

Question 8

What is the symbol equation for power? (work done)

Answer 8

P = E (J)
—-
(W) = T (s)

Question 9

How does lubrication minimize wasted energy transfers?

Answer 9

Reduces friction between 2 objects, reducing the amount of energy dissipated