Y8 Physics Topic 2 Forces and Energy

Question 1

A Force may be

Answer 1

• a push or pull

- a twist or turn

Question 2

3 Effects of a Force

Answer 2

Change in shape,
Change in direction,
Change in speed,

Question 3

Forces are measured using a

Answer 3

newtonmeter

Question 4

The unit of Force is the

Answer 4

Newton ( N )

Question 5

What is mass?

Answer 5

The matter ( atoms, molecules) in a body

Question 6

Mass is measured in…

Answer 6

kilograms( kg ) or in grams (g)

Question 7

Mass is measured using…

Answer 7

a mass balance

Question 8

Would the mass of an object change if it was on the moon?

Answer 8

No

Question 9

What is weight?

Answer 9

The gravity acting on a body, it is a force.

Question 10

Weight is measured in…

Answer 10

newtons (N)

Question 11

What is the calculation for weight on the Earth

Answer 11

Weight = mass ( kg) X Gravitational Pull

W = m x 10

Question 12

Calculate the weight of Susan : Mass = 55kg

Answer 12

Weight = mass ( kg) X Gravitational Pull
W = m x 10
W of Susan = 55 x 10
= 550 N

Question 13

Friction is…

Answer 13

a force which opposes motion

Question 14

Give some example when friction is useful and explain your answer.

Answer 14

Racing car as it stops it slipping off a track when racing.

Chalk on a snooker cue as it stops the cue slipping off the ball.

Question 15

Give some example when friction is not useful and explain your answer.

Answer 15

When a swimmer is racing as it slows them down.

Friction on ice for ice scatters as they need to glide over the ice.

Question 16

When driving a car, give examples of when friction is useful.

Answer 16

Cornering,
accelerating,
slowing down,

Question 17

When driving a car, give examples of when friction is not useful.

Answer 17

Engine,
Overheating,
drag,

Question 18

How can friction be reduced in a car engine?

Answer 18

Lubrication

Question 19

In Science pressure tells us…

Answer 19

how concentrated a force is.

Question 20

Pressure depends on…

Answer 20

1. force

2. area

Question 21

Is hammering a nail into wood high or low pressure, explain your answer.

Answer 21

The point of the nail has a very small area. The force of the hammer is concentrated on this small area. A big force pressing on a small area gives a high pressure.

Question 22

Explain why it is more difficult to hammer a blunt nail than a sharp nail into a piece of wood?

Answer 22

Blunt nail has a bigger area and so needs a bigger force to generate enough pressure to drive the nail.

Question 23

Camels are heavy animals. They walk on the soft sand of the desert, and they are in danger of sinking in. They have large flat feet, so that…

Answer 23

their weight is spread out over a large area and produces a low pressure.

Question 24

Explain why the boy sinks further into the sand than the heavier camel.

Answer 24

He has smaller feet which generate high pressure which makes him sink.

Question 25

If you stand upright on thin ice, you might be in great danger. Explain why.

Answer 25

Your weight is spread over a small area generating high pressure on the ice.

Question 26

Explain why you would use a ladder to help rescue someone who as fallen through ice on a lake.

Answer 26

Your weight is spread over a large area generating low pressure on the ice.

Question 27

AVERAGE SPEED =

Answer 27

= Total distance (D) / Total time (T)

Question 28

Danny walked 8km in 2 hours. Calculate Danny’s speed.

Answer 28

Distance travelled = 8km

Time taken = 2 hours

Average speed = Distance travelled / Time taken

= 8 / 2
= 4 km per hr

Question 29

Susan ran 100m in 20 seconds. Calculate her speed.

Answer 29

Distance travelled = 100 m

Time taken = 20 seconds

Average speed = Distance travelled / Time taken

= 100 / 20
= 5 m per sec

Question 30

Danny walked 20 km in 4 hours. calculate his speed in m/sec

Answer 30

Distance travelled = 20 km = 20 000 m

Time taken = 4 hours = 14400 secs

Average speed = Distance travelled / Time taken

= 20000 / 14400
= 1.39 m per sec

Question 31

Energy is measured in

Answer 31

Joules (J) or kilojoules (KJ)

Question 32

1 KJ = ? J

Answer 32

1000 J

Question 33

CAN YOU LIST FOUR WAYS ENERGY IS NEEDED BY HUMAN BEINGS

Answer 33

(1) walking
(2) breathing
(3) singing
(4) playing sport

Question 34

gravitational ENERGY

Answer 34

The energy an object gains when it is lifted higher

Question 35

potential ENERGY

Answer 35

Energy stored in a wound up or stretched spring

Question 36

kinetic ENERGY

Answer 36

The energy an object has because it is moving

Question 37

chemical ENERGY

Answer 37

Energy stored in fuel, foods and batteries

Question 38

electrical ENERGY

Answer 38

Carried with electric current

Question 39

light ENERGY

Answer 39

Allows us to see things around us

Question 40

heat ENERGY

Answer 40

Makes things warmer, melts solids and boils liquids

Question 41

sound ENERGY

Answer 41

Energy produced when an object vibrates and makes a noise

Question 42

nuclear ENERGY

Answer 42

Energy from within an atom. Used in Nuclear Power Stations.

Question 43

What is a Transducer

Answer 43

A device which changes energy from one form to another

Question 44

A device which changes energy from one form to another is called a…

Answer 44

Transducer

Question 45

LAW OF ENERGY CONSERVATION

Answer 45

ENERGY IS NOT CREATED OR DESTROYED

IT IS SIMPLY TRANSFERRED FROM ONE FORM TO ANOTHER

Question 46

Energy change in a torch

Answer 46

Electric - light

Question 47

Energy change in a Dynamo & Bulb

Answer 47

kinetic – electric - light

Question 48

Energy change in a Pendulum

Answer 48

potential – kinetic - potential

Question 49

Energy change in a Motor

Answer 49

electric - kinetic

Question 50

Energy change in a Buzzer

Answer 50

electric - sound