Energy Resorces and transfers

Question 1

Name the energy store that decreases/increases when natural gas is burned.

Answer 1

Decrease - chemical (energy store);
increase - heat (energy store);

Question 2

state advantages/dissadvanges of natural gas

Answer 2

Idea that electricity generated can change
to meet demand; (startup time is short)

Idea that it is reliable; (is always available, does
not depend on weather)

non-renewable / gas will eventually run
out;

burning gas produces CO2 / greenhouse
gases;

dependency on other countries to supply
gas;

Question 3

any advantages and disadvantages of wave power

Answer 3

idea that it is renewable;

produces no polluting gases;

idea that waves might not always be
present;

(may) cause harm to wildlife;

possible storm damage to the generator;

Question 4

State the formula linking gravitational potential energy, mass,
gravitational field strength (g) and height.

Answer 4

GPE = mass × g × height;

Question 5

what is meant by the term work done

Answer 5

the amount of energy transferred to an object through work.

Question 6

Justify why 7.8J of energy must be dissipated into the thermal store of the
surroundings as the load is lifted.

Answer 6

idea that energy must be conserved;
demonstration that 7.8 + 3.2 = 11(.0);

Question 7

principle of conservation of energy.

Answer 7

dea that energy can’t be created or destroyed;

both created and destroyed need to be seen for marks

Question 8

State the formula linking efficiency, useful energy output and
total energy output.

Answer 8

efficiency = useful (energy) output / total (energy) output

Question 9

(Calculate the energy transferred into the thermal store of the surroundings.) what formula

Answer 9

Input Power minus output power

Question 10

When released, 45J of energy transfers into the car’s kinetic store.
The car travels a distance of 7.5m during this energy transfer.
(i) State the useful work done on the car.

Answer 10

45 (J)

Question 11

Calculate the mean accelerating FORCE!

Answer 11

Work = Force x Distance

Question 12

temperature formula

Answer 12

Δ T = Q / mc

Q = amount of heat absorbed or released, m = mass of the body, c = specific heat of the body.

Question 13

Discuss why conduction is the main way that thermal energy is transferred from
the dog to the water.

Answer 13

Dog and water are at different temperatures;

Dog and water in physical contact so likely to
be conduction;

No movement of particles from dog to water,
so not convection / EQ;

Dog and bag are both solids, so convection
impossible;

Not much radiation as dog and water similar
temperatures;

Question 14

The person does ………………………………………………………………………………… work to twist the rubber band.
As the person twists the rubber band it extends, increasing the …………………………………………………………………………
energy store of the rubber band. When the rubber band is released it does mechanical work,
increasing the ………………………………………………………………………………… energy store of the propeller

Answer 14

mechanical;
elastic;
kinetic / gravitational;

Question 15

Describe the motion of the particles in liquid

Question 16

advantages and disadvantages of using solar power rather than fossil fuels
to generate electricity.

Answer 16

no carbon (dioxide) emissions;
no contribution to { global warming /
greenhouse effect / acid rain };
is renewable;
low maintenance/no moving parts;

needs a favourable climate;
needs long days /doesn’t work at night;
needs a lot of space;
cannot respond to rapid changes in
demand;