Forces Flashcards

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1
Q

Define physical quantity

A

A physical quantity is a physical property of a phenomenon, body, or substance, which
can be quantified by measurement.

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2
Q

Quantity symbol of time

A

t

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3
Q

Quantity symbol of mass

A

m

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4
Q

Quantity symbol of force

A

F

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5
Q

Quantity symbol of weight

A

Fg

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6
Q

Quantity symbol of charge

A

Q

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7
Q

Si unit for seconds (t)

A

s

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8
Q

Si unit for kilograms (m)

A

kg

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9
Q

Si unit for newton (F)

A

N

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10
Q

Si unit for newton (Fg)

A

N

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11
Q

Si unit for coulomb (Q)

A

C

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12
Q

What two groups are classified as physical quantities

A

Scalar quantities
Vector quantities

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13
Q

Define Scalar quantity

A

A scalar quantity is a physical quantity that has
magnitude (size) only.

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14
Q

What does scalar quantity include?

A

Mass, electric charge, time, distance (MEDT) scales of fish

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15
Q

Define vector quantity

A

A vector quantity is a physical quantity that has
magnitude and direction.

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16
Q

What does vector quantity include?

A

Force, weight, velocity, acceleration (WAVF)

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17
Q

What are the two ways of describing direction?

A

Relative direction and compass points

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18
Q

What is relative direction?

A

up, down, left, right, forwards, backwards

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19
Q

What is compass points?

A

North, east, south, west

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20
Q

How is a vector shown?

A

arrow pointing to the right written above it

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21
Q

When is arrow left out of vector?

A

If the magnitude (size) of a vector is only needed, then the arrow is omitted (left out).

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22
Q

How are vectors graphically represented?

A

Arrow defining the direction, and the length of
the arrow defines the vector’s magnitude according to a scale.

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23
Q

How are two vectors equal?

A

Equal if they have the same magnitude and direction,
regardless of whether they have the same initial points,

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24
Q

Define forces

A

A force is a push or a pull that acts in a certain
direction.

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25
Q

What two things do forces have?

A

Magnitude (size) and direction

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26
Q

What can forces change?

A

Change a body’s state of motion in a straight line.

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27
Q

How can forces be measured?

A

spring scale/spring balance/newton meter (

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28
Q

What spring scales include?

A

Spring connected to a metal hook

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29
Q

When does the spring stretch (balance)?

A

Force is applied to hook

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30
Q

When does the spring stretch long?

A

The bigger the force applied, the longer
the spring stretches and the higher the reading.

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31
Q

When describing a force, which of the following 4 points must be noted?

A

exerting the force
experiencing the force
magnitude of the force
direction force is being exerted

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32
Q

What does the length of the arrow represent?

A

Represents the magnitude of the force

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33
Q

What does the arrowhead represent?

A

arrowhead represents the direction of the force.

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34
Q

How can we also describe the direction in which a force acts?

A

cardinal points system

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35
Q

What are free body diagrams are used to represent?

A

Free body diagrams are used to represent all of the forces acting on an object graphically.

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36
Q

What happens when more than one force can act on an object at a time?

A

Multiple arrows connected to the same dot.

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37
Q

If the forces are acting in the same direction, what do you do?

A

Draw separate arrows, connected to
the same dot

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38
Q

How does one represent force?

A

uppercase ‘F’ to show that it is a force,
subscript to show who or what is exerting the force.

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39
Q

What are the effects of forces?

A

Forces do not always have an effect, but the effects that they can have are the following.

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40
Q

Name the four effects of forces

A

Motion, distortion, direction, rotation

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41
Q

What is motion?

A

change the speed of an object.
cause a stationary object to move.
cause a moving object to stop.

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42
Q

What is distortion?

A

change the shape of an object.
Elastic objects return to their original shape - force removed.
Inelastic objects are permanently distorted.

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43
Q

What is direction?

A

A force can change the direction in which
something is moving.

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44
Q

What is rotation?

A

A force can cause an object to spin.

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45
Q

Define balanced and unbalanced forces

A

The resultant force (Fnet) is the single force which
has the same effect as the original forces acting
together.

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46
Q

What is another word for Fnet?

A

Resultant force

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47
Q

Fnet = 0

A

Balanced force

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48
Q

Fnet = 0 not

A

Unbalanced force

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49
Q

When does Fnet occur?

A

When multiple forces act on the same object

50
Q

What are balanced forces?

A

Balanced forces have equal magnitudes but act in opposite directions.

51
Q

Why is the resultant force zero (balanced)?

A

They cancel each other out and the overall effect is zero

52
Q

When the forces are balanced, there is no change in the object’s state of motion:

A

A stationary object remains stationary
A moving object keeps on moving at the same speed in the same direction

53
Q

What are unbalanced forces?

A

do not have equal magnitudes
do not cancel each other

54
Q

What effects do unbalanced forces have on?

A

overall effect on the body

55
Q

How does one show forces graphically?

A

Head to tail diagrams

56
Q

How does one calculate forces graphically?

A

Algebraically

57
Q

What is the formula to determine the resultant force?

A

Fnet = F1 + F2

58
Q

What formula must one use when calculating the resultant force acting in the same direction?

A

Fnet = F1 + F2

59
Q

What formula must one use when calculating the resultant force not acting in the same direction?

A

Assign one direction positive - other negative
Fnet = F1 + F2
= + + (-)

60
Q

When describing resultant force, what must one include?

A

Magnitude and direction

61
Q

What do forces occur in?

A

Pairs

62
Q

When forces occur in pairs, what is it called?

A

• Act on two different objects
• Have the same magnitude
• Act in opposite directions

63
Q

Object A exerts force on object B

A

FA on B

64
Q

Object B exerts force on object A

A

FB on A

65
Q

Are moving forces balanced?

A

Forces are balanced when they are not moving

66
Q

What are the two types of forces?

A

Contact and non-contact forces

67
Q

Define contact forces

A

Results when interacting objects are touching. Physical contact

68
Q

What does contact forces include?

A

Friction, tension, and compression

69
Q

Which type of force is action reaction?

A

Contact forces

70
Q

Define friction

A

The force that opposes the motion of an object and which acts parallel to the surface

71
Q

Define tension

A

The stretching force that is exerted by a rope, string or wire when it is pulled by a force.

72
Q

Define compression

A

The force that pushes or squeezes something into a smaller space.

73
Q

Define non-contact forces

A

Act over a distance and occur when two interacting objects are not in physical contact with each other

74
Q

What does non-contact forces include?

A

Magnetic, electrostatic and gravitational

75
Q

What is another name for non-contact forces?

A

Field forces

76
Q

What is magnetic force exerted by?

A

Any magnet

77
Q

What is magnetic force experienced by?

A

Any magnetic material

78
Q

What type of force is magnetic?

A

Attraction/Repulsion

79
Q

What is electrostatic force exerted by?

A

Any charged object

80
Q

What is electrostatic force experienced by?

A

any charged or neutral object

81
Q

What type of force is electrostatic?

A

Attraction/Repulsion

82
Q

What is gravitational force exerted by?

A

Any object with mass

83
Q

What is gravitational force experienced by?

A

Any object with mass

84
Q

What type of force is gravitational ?

A

Attraction

85
Q

What is a magnetic force?

A

A magnetic force is a force that two magnetic materials exert on each other over a distance.

86
Q

What do magnets attract?

A

Other magnetic materials

87
Q

What material are magnetic substances?

A

Iron, cobalt, nickel

88
Q

How many poles do magnets have?

A

All magnets have two poles: a north pole and a south pole.

89
Q

Define magnetic fields

A

Regions in space around magnetic objects where magnetic force is experienced.

90
Q

Which poles attract?

A

Opposite poles attract

91
Q

Which poles do not attract?

A

like poles repel

92
Q

What type of magnet is the earth?

A

The Earth can be considered as one large bar magnet,
with a south pole and a north pole.

93
Q

Why will objects experience magnetic force?

A

The Earth has a magnetic field around it, therefore when placed within this field, objects will experience a magnetic force.

94
Q

What is the magnetic north pole of a compass is attracted to?

A

The geographical North Pole of the Earth.

95
Q

What is the North pole actually?

A

South pole of the Earth’s magnet.

96
Q

Define electrostatic force

A

An electrostatic force is a force that two electrically
charges objects exert on each other over a distance.

97
Q

When does an electrostatic field exist?

A

An electrostatic field exists around any charged
object, and another object placed in that fields will
experience a force.

98
Q

What happens when certain materials are rubbed together?

A

They can acquire an electrostatic charge as a result of
the loss or gain of electrons.

99
Q

What has a gravitational field around it?

A

Any large object (planet, the sun, the moon)

100
Q

What will experience gravitational attraction?

A

any object placed in that field will experience a force of attraction.

101
Q

What does the magnitude of the gravitational force of attraction between two objects depends on?

A

The mass of the objects
The greater the distance

102
Q

What does objects with a larger mass exert?

A

a greater force of attraction

103
Q

What type of force does the greater the distance between the two objects create?

A

the smaller the force

104
Q

What is gravity?

A

‘Gravity’ is the gravitational force of attraction that the Earth exerts on all objects.

105
Q

Which direction does gravity act?

A

vertically downwards, towards the centre of the Earth.

106
Q

What is gravity also called?

A

Weight

107
Q

Define weight

A

Weight is the gravitational force that the Earth exerts on any object on or near its surface.

108
Q

Is mass and weight the same thing?

A

No

109
Q

Unit for weight

A

Newton

110
Q

What does weight depend on?

A

Depends on where the object is (variable)

111
Q

How is weight measured?

A

Measured using a spring scale/balance

112
Q

Define mass

A

A measure of the quantity of matter possessed by an object

113
Q

Unit for mass

A

Kilogram

114
Q

What does mass depend on?

A

Constant regardless of where the object is

115
Q

How is mass measured?

A

Measured using a triple beam balance

116
Q

What do balances determine?

A

A balance determines mass by balancing an unknown mass against a known mass

117
Q

How do scales determine weight?

A

Most weighing scales use sets of springs to measure the force acting on a mass to determine weight.

118
Q

Formula for gravitational force

A

Fg = mg

119
Q

What is the acceleration due to gravity for earth?

A

9,8

120
Q

What is the acceleration due to gravity for moon?

A

1,6