P1

Question 1

What are the ways energy can be transferred

Answer 1

-By heating
-by waves
-by an electric current
-by a force when it moves an object

Question 2

What happens to an object when it falls and gains speed

Answer 2

Its store of gravitational potential energy decreases and kinetic energy store increases

Question 3

What ways can energy be transferred

Answer 3

Heating, waves, electric current, by moving force

Question 4

What energy is transferred in a falling object

Answer 4

Gravitational potential energy decreases, kinetic potential energy increases

Question 5

What energy is transferred when an object hits the ground without bouncing

Answer 5

Kinetic energy store decreases, most energy transferred to surroundings and thermal energy store of surroundings increases

Question 6

What is the conservation of energy principle

Answer 6

Energy cannot be created or destroyed

Question 7

Where does conservation of energy apply

Answer 7

All energy changes

Question 8

What is a closed system?

Answer 8

A place where no energy is transferred into or out of the system but can be transferred within it

Question 9

What is work done

Answer 9

Energy transferred when an object is moved

Question 10

Equation involving Force Distance and Work done

Answer 10

Work done = Force applied x distance moved from force

Question 11

What force do you need to lift an object upwards

Answer 11

A force Equal to The weight (m x gf) of the object

Question 12

What happens to gravitational potential energy stores when an object moves upwards

Answer 12

increases = work done by lifting force

Question 13

What happens to gravitational potential energy stores when an object moves down

Answer 13

Decreases = to work done by gravity

Question 14

Equation for change in gravitational energy store

Answer 14

Change in GES(J) =W(N) x Change in Height (M)

Question 15

Equation for kinetic energy store

Answer 15

Kinetic energy (J) = 1/2x mass (Kg) x Speed(m/s^2]

Question 16

Equation for emergy store of stretched elastic spring

Answer 16

Elastic potential energy (J) = 1/2x spring constant (N/m) x extension^2 (m^2)

Question 17

What arebthe factors for the amount of kinetic enery in a kinetic energy store

Answer 17

Mass and speed

Question 18

What is elastic potential energy?

Answer 18

The amount of energy stored in an elastic object when work is done on it

Question 19

What is useful energy

Answer 19

Energy in the place we want it and the form we need it

Question 20

What is wasted energy?

Answer 20

Energy that is not useful and transferred by an undesired pathway

Question 21

What happens when energy dissipates (spreads out)

Answer 21

It gets less and less useful

Question 22

What happens to wasted energy

Answer 22

Its eventually transferred to the surroundings which become warmer

Question 23

Why might machines waste energy

Answer 23

-Friction between moving parts
-air resistance
-electrical resistance
-noise

Question 24

How can you reduce the problem of friction wasting energy in machines

Answer 24

Lubricate the moving parts

Question 25

What is the equation for effiency

Answer 25

Efficiency = useful output energy transferred by the device / total input energy supplied to the device

Question 26

What is input energy

Answer 26

Energy supplied to the device

Question 27

What is output energy

Answer 27

Energy transferred by the device

Question 28

What energy do you use at home

Answer 28

Gas, electricity, oil.

Question 29

Why are electrical appliances efficient

Answer 29

Because they are designed for a particular purpose so should waste as little energy as possible

Question 30

Examples of everyday electrical appliances

Answer 30

-Heating
-lighting
-producing sound and visual images (tv, radio)
-eletrical motors that make things move (toys, blender)