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Flashcards in Science Forces Deck (32)
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Forces are either.....

A push
Or
A pull

1

Forces are measured by a ........ in .........

Neuton meter
Neutrons

2

Name the different types of forces.

Electrical
Friction
Gravity
Magnetic

3

What are the properties of vectors?

Vectors have direction and size.

4

Complete:
For every action force....

There is an equal and opposite reaction force.

5

What happens if an object has no resultant force acting on it?

If it is at rest it stays at rest.
If it is moving it keeps moving at a constant speed in a straight line.

6

How can a force be shown (depicted)?

With a vector.

7

What does a vector look like?

It is a dot with a line and an arrow.

8

What does the dot in a vector show?

The dot shows where the force begins.

9

What does the length of the line in a vector show?

The length of the line shows the amount of force.

10

What does the arrow in a vector show?

The arrow shows the direction of the force.

11

If a book is lying on a table how would you describe the forces?

The forces are balanced.

12

If an object has a resultant force acting on it then.....

its speed or direction will change.

13

What is the formula for weight on earth?

W = m x 10

14

What is the formula for mass?

M = w/10

15

What do you call the turning effect of a force?

A moment

16

On what does the turning effect (moment) of a force depend?

It depends on its size and where it is applied.

17

The further away the force, the ........ The moment.

Bigger

18

The bigger the force the ......... the moment.

bigger

19

What is the formula for the moment of a force?

Moment = F x d
force x distance

20

Define 'F'

F = force in newtons (N)

21

Define 'd'

d = distance in metres (m) in centimetres (cm)

22

What is moment measured in?

Newton metres (Nm) or Newton centimetres (Ncm)

23

In which direction do moments act?

Moments act in either a clockwise or an anti-clockwise direction.

24

State the principle of moments.

If equilibrium (balanced), the total clockwise moment equals the total anti-clockwise moment. ( which is a fancy way of saying nothing moved!)

25

In levers, what do you call the point about which it turns?

A pivot or fulcrum

26

In levers, what do you call the part you are trying to move?

The load

27

In levers, what do you call the force you are using to move it?

The effort (which is why they say 'move it! Make more effort!)

28

What is the formula for density?

density (Kgm3*) = mass (kg)/volume (m3*)

29

How do you measure the density of regular solids?

1. Measure the mass using a top pan balance.
2. Measure the dimensions of the solid using a ruler and calculate the volume (l x b x h).
3. Apply the formula density = m/v.

30

How do you measure the density of irregular solids?

Use the displacement method: (bath time!)
1. Find the mass of the object using the top pan balance.
2. The volume is found by measuring the increase in the level of water in a measuring cylinder.
3. Apply the formula density = m/v

31

How do you measure the density of liquids?

1. Measure the mass of a dry empty cylinder.
2. Pour in a known volume of liquid.
3. Measure the mass of the cylinder + liquid.
The difference between the reading at no 2 and the reading at no 3 is the mass of the liquid.
4. Apply the formula density = m/v