P1: Energy

Question 1

Name 4 energy stores

Answer 1

Gravitational potential, Kinetic, Chemical and electrical

Question 2

Describe the energy transfers that occur as a ball falls to the ground

Answer 2

A ball dropped from height is accelerated downwards by gravity so the energy transfer is gravitational potential energy. The energy is then transferred to the kinetic energy store as it starts to move down.

Question 3

Equation for finding the energy in a objects kinetic store

Answer 3

Kinetic energy=1/2 x mass x velocity squared

Ek=1/2mv2

Question 4

If energy is transferred to a objects kinetic store what happens to the speed

Answer 4

When energy is transferred to the object’s kinetic store it speeds up, when it is taken away it slows down

Question 5

Give the equation for finding an objects gravitational potential store

Answer 5

Ep=mass x gravitational field strength x height

Question 6

What type of energy is transferred when you compress a spring

Answer 6

Elsatic potential energy

Question 7

Definition of an object’s specific heat capacity

Answer 7

The amount of energy needed to raise the temperature of a 1kg object by at least 1°C

Question 8

Give the equation that links energy transferred to SHC

Answer 8

Change in thermal energy=mass x SHC x temperature change

Question 9

Deacribe an experiment to find the SHC of a object

Answer 9

You would need a block of solod material and put two holes in it. The n measure the mass of the block and wrap it in a insulating layer to reduce energy transferred to the surroundings. Then insert the thermometer and heater into the two holes in the material. Measure the initial tempearure and then set the power supply to 10V and start a stop watch. Take temperature of the readings every 10 minutes.

Question 10

State the conservatioj of energy principle

Answer 10

This states that energy cannot be created or destroyed just transferred and stored.

Question 11

Define power and give two equations to calculate it

Answer 11

Power is the rate of energy transfer or the rate of doing
P=Energy transferred/time
P=Work done/time

Question 12

What are the units of power

Answer 12

Watts

Question 13

How can you remove unwanted energy transfer in a machine with moving, touchimg components

Answer 13

Lubricants

Question 14

True or false? A high thermal conductivity means there is a high rate of energy transfer

Answer 14

True

Question 15

Give 4 ways to reduce unwanted energy transfers in a home

Answer 15

You could use double glazed windows, cavity walls, loft insulation and draught exclusion

Question 16

True or false? Thicker walls make a house cool down quicker

Answer 16

False

Question 17

What is the efficiency of an energy transfer? Give the equation that relates efficiency to power.

Answer 17

The efficiency of a energy transfer is the less energy that is wasted.
Efficiency=useful power output/total power output

Question 18

Name 4 renewable and non-renewable energy resources

Answer 18

Non renewable: oils, coal and natural gas

Renewable: solar, wind, hydro-electricity and geothermal

Question 19

What is the difference between renewablw and non-renewable sources

Answer 19

Non-renewable resources will run out at one point whereas renewable tesources will never run out as they are manufactured