Forces Flashcards Preview

Abi Science 2016 > Forces > Flashcards

Flashcards in Forces Deck (167):
1

What happens when a pushing and a pulling force are both exerted on an object?

It can twist

2

What is the scientific term for a twist?

Torsion

3

What can a force do?

It can affect motion
It can change the direction of the movement
It can change the shape of an object

4

How do you reduce the amount of force needed to move an object?

Reduce the amount of friction

5

What kind of relationship is there between friction and force?

Direct

6

What is compression?

When a pushing force is applied to both sides of an object

7

What is changing the shape of an object with forces called?

Deformation

8

How do forces affect motion?

Speed up
Slow down
Start
Stop

9

What is velocity?

The rate of change of the position of an object
The speed of the object and the direction it is moving

10

What is a constant velocity?

The same speed in the same direction

11

What is it called when an object is moving at the same speed?

Constant speed

12

What is it called when an object moves faster?

Acceleration

13

What is it called when an object slows down?

Negative acceleration

14

What is an agent of motion?

Something that applies a force to another object

15

What happens when a force is applied to an object?

The object will apply a force that is equal in magnitude and opposite in direction

16

What is the scientific word for strength?

Magnitude

17

What does it mean when a force is applied to an object and it does not move?

The object is applying a force that is equal in magnitude and opposite in direction

18

What happens when two forces are applied to one object?

They combine to make a net/overall force

19

When you draw force diagrams, what is important?

If a force has a greater magnitude, the arrow line showing the force will be longer

20

What is a resultant force?

When the net force is greater than 0N

21

What kinds of forces are there?

Contact forces
Non- contact /field forces

22

What are the three types of field forces?

Magnetic
Gravitational
Electric field

23

What is friction?

The force which opposes motion between substances as they rub against one another

24

How does friction act?

In the opposite direction of the object that is moving

25

What is normal force?

The force that pushes back on something that is resting on it

26

How does normal force act?

Perpendicularly to the object that is resting on the other object

27

What will the net force of an object sitting on a desk be?

0N

28

What is the relationship between your weight and mass?

Multiplied by 9.8

29

Which direction does friction act in?

90° to the force of gravity (weight)

30

What is a scientific term for weight?

Force of gravity

31

What surface creates more friction?

Rough

32

What is an applied force?

It moves an object in a specific direction

33

What is a force of friction?

Opposite direction to movement

34

What is a force of weight or a force of gravity?

Pulls objects towards an object that has gravity

35

What is the force of normal?

Solid surface pushes an object up

36

What is the definition of weight?

The effect of gravity on mass

37

What does friction depend on?

The type of surface on which an object is moving

38

What do you need to do to get an object to move?

Overcome the force of friction
Overcome the force of weight

39

How many Newtons is the force of gravity on Earth?

9,8

40

How do you write net force?

The value of the force
The measurement of the force (Newtons)
The direction of the force

41

What effect does friction have on the speed of a force?

More friction reduces the speed of an object

42

Is friction good or bad?

It depends on the situation

43

When is friction bad?

When it reduces speed

44

When is friction good?

It helps with grip

45

What are applied forces?

Friction
Normal
Tension
Compression

46

What kind of force is tension?

A pulling force

47

What kind of force is compression?

Pushing

48

What does a tension force do?

It changes the shape
It stretches an object

49

What does a compression force do?

Changes the shape
Squashes an object

50

What applied forces occur in a bridge?

Tension and compression

51

What does this formula stand for?
F=mxa

Force is equal to mass times acceleration

52

What is a field?

A field is a region in space where an object (with certain properties) will experience a force.

53

Can field forces touch the object on which they are exerting their force?

Yes
They do not have to be touching, but they still work when touching

54

What is the law of gravity?

Any object that has mass has gravity

55

What kind of relationship is there between gravity and mass?

Direct

56

What effect does distance have on field forces?

If an object is further away then the force will not be as strong

57

What are the factors of field forces?

Repulsion
Attraction

58

What are the factors of contact forces?

Push
Pull

59

What are the two sides of a magnet called?

Poles

60

What are the two poles of a magnet called?

North
South

61

What force does the North Pole of a magnet exert?

Repulsion

62

What force does the South Pole of a magnet exert?

One of attraction

63

What force does Fapplied act with?

Ffriction

64

How do Fn and Fg act?

Vertically

65

How do Fa and Ff work?

Horizontally (generally)

66

What does it mean when forces are balanced?

When two opposing forces ( Fapplied & Ffriction, Fravitational & FNormal) are equal in magnitude and opposite in direction

67

How can Fapplied = Ffriction?

If an object is moving at a constant speed

68

What kind of force is gravitational?

Field
Attraction

69

What is a force?

A push or a pull on an object

70

What are forces measured in?

Newtons (N)

71

Why do we use Newtons to measure forces?

It is named after Sir Isaac Newton

72

Who was Isaac Newton?

A mathematician and a physicist
He came up with the three laws of motion

73

Where do we use forces?

In everything we do

74

Give examples of how we use forces every single day of our lives?

Our muscles PULL on our bones to make us move
Our feet PUSH on the ground when we walk
We PUSH to open doors
We PULL our food up to our mouths

75

What does pushing in solid objects do?

It makes them accelerate

76

What does it mean when an object accelerates?

It gains more speed

77

What is speed?

It describes how fast an object is moving

78

What is the definition of acceleration?

It is a measure of how an object's speed changes every second

79

What is an agent of force?

The thing that applies a force

80

How do forces act?

In pairs

81

What happens to an object when the Fapplied is equal to the Ffriction?

The object will not move

82

Which direction will an object move?

In the direction of the greater force

83

What happens when an object exerts a force on another object?

The object pushes back

84

What was Newton's law about actions and reactions?

For every action, there is are action that is equal in magnitude and opposite in direction

85

Can more than one force act on an object?

Yes

86

What is net force?

The overall combined force exerted on an object

87

How do we represent the forces acting on a body?

With free body diagrams

88

How do we represent forces in a free body diagram?

With vectors (arrows)

89

How do we represent bodies in free body diagrams?

With a dot

90

How do we show magnitude in a free body diagram?

By the length of a vector

91

What kind of force is gravity?

A force of attraction

92

Where does gravity pull you?

Towards the CENTRE of the Earth

93

What are the two factors that affect the magnitude of a gravitational force?

How close the objects are
The mass of the object

94

What is weight actually measured in?

Newtons

95

Why is weight not actually measured in kg?

Weight is the effect of gravity on an object
Not the mass in an object

96

What is the formula for weight?

Fw=mxg

97

How do you measure a force?

With a spring balance

98

How do Spring balances work?

According to Hooke's Law

99

What is Hooke's Law?

It says that the distance that a spring moves from its resting position is directly proportional to the force that is exerted on the spring

100

Give four examples of contact forces?

Force of compression
Force of tension
Force of friction
Force of normal

101

What does friction do to an object?

It resists the movement of an object

102

What is the relationship between friction and mass?

The greater the mass, the more magnitude the applied force will need to overcome the force of friction

103

How do you move an object?

You apply a force greater than the force of friction

104

What is tension?

When an applied force is transferred from one object to another e.g. When a person pulls a rope, which then has tension, the rope pulls the block

105

What is the difference between tension and compression?

Tension pulls/stretches an object
Compression pushes/squashes

106

What are compression forces?

Two forces acting on an object that are opposite in direction (towards one another)

107

What are tension forces?

Two forces acting in opposite directions (pulling away from one another)

108

Does repulsion push or pull an object?

Pushes away from itself

109

Does attraction push or pull?

Pulls toward itself

110

Where does gravity exist?

Between any two objects that have mass

111

What relationship do gravity and mass have?

Direct
The greater the mass the greater the gravity

112

What is mass?

The amount of matter in an object

113

Is weight constant?

No

114

Why isn't weight constant?

Mass can change
The magnitude of the force of gravity can change

115

What is an object on free fall?

An object that only has the force of gravity acting on it

116

What are magnets?

Objects that have a strong magnetic pull

117

What do all magnets have?

A North Pole and a South Pole

118

What are magnetic materials?

Materials that are attracted to magnets

119

What are the magnetic materials?

Iron
Nickel
Cobalt

120

What forces do like poles exert on each other?

Repulsion

121

What forces do unlike poles exert on each other?

Attraction

122

What is a magnetic field?

The space around a magnet in which it can exert a force

123

What are field lines?

Lines in a diagram that represent a force field

124

How are strong force fields represented?

With field lines that are close together
The more field lines there are, the greater the magnitude of the force

125

Which way do field lines on a magnet go?

From North to South
Away from North
Towards South

126

Does the Earth have a magnetic field?

Yes

127

What is the magnetic field of the Earth like?

There is a North and a South Pole, just like a bar magnet

128

Where is the magnetic North Pole of the Earth?

At the South Pole

129

Where is the magnetic South Pole of the Earth?

At the North Pole

130

How do compasses work?

They respond to the Earth's magnetic field

131

What are ferrofluids?

Liquids that can become magnetised in the presence of a strong magnetic field

132

What causes the Northern lights?

Charged particles (from the sun) that escape the belts (areas in Earth's atmosphere that occur because of the magnetic field) and spiral towards the magnetic poles. They then interact with gas particles and cause light shows

133

What causes static electricity?

Friction between two objects which are being moved

134

What can friction between two surfaces cause?

Electrons to be transferred

135

What can happen when electrons jump from one surface to another?

The surfaces' charges could change

136

What is the type of charge is in a proton?

Proton

137

How are electrons charged?

Negatively

138

Where are electrons positioned in an atom?

Around the nucleus

139

What is the nucleus made up of?

Protons and neutrons

140

How are neutrons charged?

They have no charge

141

How is an atom held together?

By electrostatic attraction between the negatively charged electrons and the positively charged protons

142

How can atoms be neutral?

If the amount of protons and electrons is balanced

143

When is an object negatively charged?

When it has more electrons than protons

144

When is an object positively charged?

When it has less electrons than protons

145

What causes an electrostatic force of repulsion?

When two objects with like charges are brought close together

146

What causes an electrostatic force of attraction?

When like charges are brought close to each other

147

What affects the magnitude of an electrostatic force?

Objects that are closer have a greater force
Objects that are more charged have a stronger force

148

What is an electrostatic discharge?

When extra electrons jump from a negatively charged object to a positively charged object, to balance the charges

149

What is lightning?

An electrostatic discharge between the clouds and the ground

150

Who are clouds charged?

Negative on the bottom
Positive on the top

151

What is thunder?

The sound released during the discharge of electrons from a cloud to the ground

152

What causes the difference of charges in a cloud?

Friction between particles in the cloud

153

What is the action? (According to Newton's law)

The force acting on the object

154

What is the reaction? (According to Newton's law)

The force that the object exerts back in the opposite direction. It will be equal in magnitude

155

How many forces can act on an object?

More than one

156

What are contact forces?

forces that act when objects are in contact (touching) with each
other

157

Does mass change depending on where you are?

No

158

Does weight change depending on where you are?

Yes. If where you are has a different gravitational force, your weight will change

159

Can magnets work through substances?

Yes, if it is a strong enough magnet

160

What is free-fall?

When the only force acting on an object is gravitational

161

Why do astronauts float when in free fall?

Because they are in a spaceship, which is moving at the same speed that they are

162

What is an alloy?

A mix of more than one metal

163

What is the relationship between Fapplied and Fweight?

Direct
The greater the mass of something the greater the magnitude of force applied to cause motion

163

What do you need to remember about drawing free body diagrams?

Do not draw the object
Just draw a small circle in the centre

163

What are vectors?

Arrows

163

How does the force of normal compare to the force of gravity?

They are equal in magnitude but opposite in direction

163

What force does FNormal act with?

Fgravitational
Fweight