SP2d Efficiency and Stored Energies

Question 1

Change in gravitaional potential energy (J) = ?

Answer 1

mass (kg) x gravitational field strength (N/kg) x change in height (m)

Question 2

Kinetic energy (J) = ?

Answer 2

½ x mass (kg) x speed² (m/s)

Question 3

Kinetic energy is proportional to?

Answer 3

the square of speed, KE ∝ v² (and/or) mass, KE ∝ m

Question 4

When an object falls, energy from its gravitational potential store is ?

Answer 4

transferred to its kinetic store.

Question 5

The further an object falls the ?

Answer 5

faster it goes because of gravity.

Question 6

Energy lost from GPE store, is equal to ?

Answer 6

energy gained in the KE store.

Question 7

Efficiency = ?

Answer 7

useful energy transferred by the device
total energy supplied to the device

             useful en out
              useful en in

Question 8

To improve efficiency we need to ?

Answer 8

increase energy that is usefully tansferred by reducing wasted energy transferred.

Question 9

What is efficiency ?

Answer 9

a comparison of the energy output to the energy input in a given system.