Motion, Forces and Energy Flashcards

You may prefer our related Brainscape-certified flashcards:
1
Q

How can you find a length?

A

using a ruler or tape measure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

How can you find a volume?

A

using a measuring cylinder

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

How can you measure a variety of time intervals?

A

using clocks and digital timers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

centi=

A

divide by 100

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

milli=

A

divide by 1000

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

kilo=

A

times by 1000

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

mega=

A

times by 1 000 000

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

giga=

A

times by 1 000 000 000

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is a scalar quantity?

A

a quantity that has only magnitude

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is a vector quantity?

A

a quantity that has both magnitude and direction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are some scalar quantities?

A
  • distance
  • speed
  • time
  • mass
  • energy
  • temperature
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are some vector quantities?

A
  • force
  • weight
  • velocity
  • acceleration
  • momentum
  • electric field strength
  • gravitational field strength
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is speed?

A

distance travelled per unit time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

speed formula

A

v = s/t

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is velocity?

A

speed in a given direction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

formula for average speed

A

total distance travelled/total time taken

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What shows CONSTANT SPEED on a DISTANCE-TIME graph?

A

a straight, sloping line

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What shows A HIGHER CONSTANT SPEED on a DISTANCE-TIME graph?

A

a straight, sloping line of higher gradient

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What shows STATIONARY object on a DISTANCE-TIME graph?

A

flat/horizontal line

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

On a distance-time graph, a flat horizontal line means?

A

the object is stationary

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

On a distance-time graph, a straight sloping line means?

A

constant speed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

On a distance-time graph, a straight sloping line with a higher gradient means?

A

higher constant speed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

How can you calculate speed from a distance–time graph?

A

find the gradient

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

For a speed–time graph, a flat horizontal line at zero speed means?

A

stationary

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

When is an object stationary in a speed-time graph?

A

flat horizontal line at zero speed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

For a speed–time graph, a flat horizontal line (>0) means?

A

constant speed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

When is an object in constant speed in a speed-time graph?

A

a flat horizontal line above zero speed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

For a speed–time graph, an upward sloping line means?

A

accelerating; the steeper the gradient, the higher the acceleration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

When is an object accelerating in a speed-time graph?

A

an upward sloping line

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

For a speed–time graph, a downward sloping line means?

A

deceleration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

When is an object decelerating in a speed-time graph?

A

downward sloping line

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

How can you measure distance in a speed-time graph?

A

Calculate the area under the speed–time graph

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

What is the acceleration of free fall g for an object near to the Earth’s surface?

A

approximately constant and is approximately 9.8 m/s2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

What is acceleration?

A

change in velocity per unit time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

formula acceleration

A

a = ∆v / ∆t

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

What indicates constant acceleration in a speed-time graph?

A

a straight line

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

What indicates changing acceleration in a speed-time graph?

A

a curved line

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

How can we calculate acceleration from a speed-time graph?

A

finding the gradient

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

What is a deceleration?

A

a negative acceleration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

Describe the motion of objects falling in a uniform gravitational field without resistance.

A

after dropping, immediately accelerates because gravity pulls the ball downwards
all objects fall with same rate of acceleration, no matter their mass

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

Describe the motion of objects falling in a uniform gravitational field with resistance.

A

gravity produces a force pulling downwards, but air resistance pushes back upwards. The more air resistance, the smaller the acceleration.
Eventually, downwards force of gravity is balanced by air resistance, preventing any more acceleration, reaching terminal velocity.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

What is terminal velocity?

A

The top speed reached by any object experiencing air resistance or a similar resistance force.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

What is mass?

A

a measure of the quantity of matter in an object at rest relative to the observer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

What is weight?

A

a gravitational force on an object that has mass

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

What is gravitational field strength?

A

force per unit mass, equal to the acceleration of free fall

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

formula for gravitational field strength

A

g = W/m

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

formula for weight

A

w = mg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

How can weights and masses be compared?

A

using a balance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

What is a balance used for?

A

to compare masses and weights

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

What is weight, in extended terms?

A

the effect of a gravitational field on a mass

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

What is density?

A

mass per unit volume

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

Formula for density

A

p = m/v

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

How can you determine a liquid’s density?

A
  • place empty measuring cylinder balance and tare the balance
  • pour liquid into the measuring cylinder
  • record mass from balance and volume from the measuring cylinder
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

How can you determine a regular solid’s density?

A

measure mass by balance and volume of shape

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

How can you determine an irregular solid’s density?

A
  • fill measuring cylinder around half-full with water
  • find mass of the object
  • measure initial volume of liquid
  • place the object into the water. Take a new reading.
  • repeat with different starting amounts of water to find its volume
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
56
Q

1 cmˆ3 of water =

A

1ml or 1g

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
57
Q

1000 cmˆ3 of water =

A

1 litre or 1kg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
58
Q

1 mˆ3 of water =

A

1000 litres or 1000kg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
59
Q

How can we determine whether an object floats?

A

seeing if its density is bigger than or smaller than water’s (1 g/cmˆ3)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
60
Q

What may forces produce?

A

changes in the size and shape of an object

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
61
Q

If no forces act on it, what occurs to an object?

A

either remains at rest or continues in a straight line at constant speed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
62
Q

What may a resultant force change?

A

the velocity of an object by changing its direction of motion or its speed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
63
Q

What is the spring constant?

A

force per unit extension

64
Q

formula for spring constant

A

k = F/x

65
Q

What is the limit of proportionality? How can we identify it on a graph?

A

highest force that can be applied before extension of a spring/wire is no longer proportional to force applied, deformation occurs above this point
straight line begins to curve

66
Q

force =

A

ma (force and acceleration are in the same direction)

67
Q

What is solid friction?

A

the force between two surfaces that may impede motion and produce heating

68
Q

What will friction act on?

A

an object moving through a liquid
or a gas (e.g. air resistance)

69
Q

What is the moment of a force?

A

a measure of its turning effect

70
Q

For any system to balance, the clockwise and anticlockwise moments must be ______.

A

equal

71
Q

What is the principle of moments?

A

A system will not rotate if the clockwise and anti-clockwise moments are equal

72
Q

How can you increase the moment (turning force)?

A

increase the force or distance from the pivot

73
Q

What does the moment (turning force) depend on?

A

size of the force and the distance of the force from the pivot

74
Q

equation for size of the moment

A

moment (Nm) = force (N) × perpendicular distance to the pivot (m)

75
Q

unit for moment

A

Nm

76
Q

When is an object in equilibrium?

A

when there is no resultant force and no resultant moment

77
Q

Describe an experiment to demonstrate that there is no resultant moment on an object in equilibrium.

A
  • place ruler on glass prism (pivot)
  • place pivot underneath centre of the ruler, ensure ruler is balanced
  • place mass A 10 cm from pivot, then place an identical mass 10  cm from pivot in other direction, the ruler should balance
  • move Mass B so it is further from the pivot, ruler is no longer balanced
78
Q

What is center of gravity?

A

imaginary point within an object that the mass and weight of the object is evenly dispersed around

79
Q

Describe an experiment to determine the position of the centre of gravity of an irregularly shaped plane lamina.

A
  • cut out irregular shape
  • make a hole near the edge of the shape and place a pin through it
  • clamp pin and make sure card can rotate
  • tie a mass suspended by cotton from the pin
  • once cotton and card have stopped moving, mark where the cotton is aligned on the card by drawing a line along its length
  • repeat, see where lines intersect (centre of gravity)
80
Q

Describe the effect of the position of the centre of gravity on stability.

A

centre of mass down low - more stable
centre of mass directly above base - stable
bigger base - more stable

81
Q

momentum =

A

mass × velocity

82
Q

momentum formula

A

p=mv

83
Q

impulse =

A

force × time for which force
acts

84
Q

impulse formula

A

impulse = F∆t
impulse = ∆(mv) = (change in momentum)

85
Q

What happens when two objects collide?

A

both objects change velocity, some (or all) of the momentum of the first object is transferred to the second

86
Q

What is conservation of momentum?

A

in any collision, the total momentum before and after the collision is
the same

87
Q

What is resultant force?

A

change in momentum per unit time

88
Q

formula for resultant force

A

F= ∆p (momentum) / ∆t (time)

89
Q

What are different stores of energy?

A
  • kinetic
  • gravitational potential
  • chemical
  • elastic (strain)
  • nuclear
  • electrostatic
  • internal (thermal)
90
Q

How can energy be transferred between stores?

A

mechanical work done, electrical work, waves and heat

91
Q

Example of energy transfer by mechanical work.

A

forces making things move

92
Q

Example of energy transfer by electrical work.

A

electric currents

93
Q

Example of energy transfer by waves.

A

light and sound

94
Q

Example of energy transfer by heat.

A

such as from a gas cooker

95
Q

What is the principle of conservation of energy?

A

energy cannot be created or destroyed, only converted from one store to another

96
Q

eq. for k.e

A

k.e = 1/2 mvˆ2

97
Q

equation for the change in gravitational potential energy

A

∆Ep = mg∆h

98
Q

mechanical/electrical work done=

A

energy transferred

99
Q

equation for mechanical working

A

W=Fd=∆E

100
Q

What are some ways that useful energy may be obtained?

A
  • chemical energy from fossil fuels or biofuels
  • water (waves, tides, dams)
  • geothermal
  • nuclear fuel
  • generate electrical power from sunlight
  • infrared/other electromagnetic waves from Sun to heat water + be source of wind energy
101
Q

What energy sources aren’t originally from the Sun?

A

nuclear, tidal and geothermal

102
Q

What is the main source of energy for all our energy resources?

A

radiation from the Sun

103
Q

How is energy released in the Sun?

A

nuclear fusion

104
Q

Advantages/disadvantages of fossil fuels

A
  • high power output, cheap, 24h/per day output
  • non-renewable, produces greenhouse gases
105
Q

Advantages/disadvantages of nuclear

A
  • high power and 24h/day output,
    no greenhouse gases
  • non-renewable,
    radioactivity risks, expensive to build
106
Q

Advantages/disadvantages of hydroelectric

A
  • renewable resource, no greenhouse gases, high power output
  • disrupts animal habitats, displaces people, needs a big river, expensive to build
107
Q

Advantages/disadvantages of tidal

A
  • renewable resource, no greenhouse gases, high power output
  • needs high tides (not common) blocks large area of sea,
    expensive to build
108
Q

Advantages/disadvantages of wave

A
  • renewable resource, no greenhouse gases
  • new technology, not reliable, low power output
109
Q

Advantages/disadvantages of solar

A
  • renewable resource, no greenhouse gases
  • unreliable, needs sunshine, low power output, expensive to build
110
Q

Advantages/disadvantages of wind

A
  • renewable resource, no greenhouse gases, cheap to operate
  • unreliable, needs wind, low power output per turbine, expensive to build
111
Q

Advantages/disadvantages of geothermal

A
  • renewable resource, no greenhouse gases, reliable output
  • only a few volcanic countries, relatively low power output
112
Q

What is meant by efficiency of energy transfer?

A

how much energy isn’t wasted in a system

113
Q

In what area of energy resources is extensive research being carried out?

A

investigation on how energy released by nuclear fusion can be used to produce electrical energy on a large scale

114
Q

efficiency =

A

(useful energy output) / (total energy input)
Or
(useful power output) / (total power input)

115
Q

What is power?

A

work done per unit time or energy transferred per unit time

116
Q

equations for power

A

P= W/t
P= ∆E/t

117
Q

What is pressure?

A

force per unit area

118
Q

equation for pressure

A

p = F/A

119
Q

Describe how the pressure beneath a liquid surface changes with depth/density of liquid.

A

the higher/deeper the liquid column, the greater the pressure.
the denser the liquid, the greater the pressure.

120
Q

equation for the change in pressure beneath the surface of a liquid

A

∆p = ρg∆h

121
Q

what is inertia

A

Inertia is a property of matter that causes it to resist changes in motion until acted upon by an external force. According to Newton’s first law of motion, an object with a given velocity maintains that velocity unless acted on by an external force. Inertia is the property of matter that makes this law hold true.

122
Q

why is mass a property that resists changes in motion

A

The greater the mass of an object, the more difficult it is to speed it up, slow it down or change its direction.
This property of mass is sometimes referred to as inertia
Mass is that quantity that is solely dependent upon the inertia of an object

123
Q

what is an experiment to determine density of a liquid

A

measure the mass through a balance and the volume through a measuring cylinder. next, follow the formula to obtain your result

124
Q

experiment to determine the density of a regular shape

A

measure the volume by doing the necessary formula and calculations. measure the mass on a scale. divide the mass by the volume

125
Q

how will you determine if an object sinks of floats

A

if the density of the object is less than 1 (density of water), it will float. otherwise, it will sink

126
Q

what is friction

A

force between two surfaces which impedes motion and results in
heating.

127
Q

formula for force in hooke’s law

A

force = k (spring constant) x X (extension)

128
Q

what is a form of friction

A

air resistance

129
Q

what is hooke’s law

A

the displacement or size of the deformation is directly proportional to the force applied.

130
Q

what is limit of proportionality

A

the point beyond which Hooke’s law is no longer true when stretching a material

131
Q

significance of the ‘limit of proportionality’ for an extension–load graph

A

the object does not return to its original length when the force is removed

132
Q

what is the law of conservation of momentum

A

In the absence of external forces (such as friction), the total momentum of a system remains the same
This means that in a collision, the sum of the momentums before the collision will be the same as the sum of momentums after the collision

133
Q

what is the formula for change in momentum

A

change in momentum = MVinitial - MVfinal

134
Q

equation for the conservation of momentum

A

(m1 x v1) + (m2 x v2) = total mass x V

135
Q

what are the two formulas for impulse

A
impulse = change in momentum
impulse = force x time
136
Q

what is the law of conservation of energy

A

energy can neither be created nor destroyed - only converted from one form of energy to another

137
Q

what is gravitational potential energy

A

energy something gains when you lift it up, and which it looses when it falls

138
Q

what is kinetic energy

A

energy of a moving object

139
Q

what is elastic energy

A

energy of a stretched spring or elastic band

140
Q

what is chemical energy

A

energy contained in a chemical substance

141
Q

what is nuclear energy

A

energy contained in the nucleus of an atom

142
Q

what is internal energy

A

energy something has due to its temperature

143
Q

what is the formula for kinetic energy

A

mvˆ2/2

144
Q

what are the types of energy stores

A

elastic, chemical, gpe, and nuclear

145
Q

what are the types of energy transfers

A

kinetic, thermal, sound, electrical, light

146
Q

what is internal energy

A

energy something has due to its temperature

147
Q

what is the formula for kinetic energy

A

mvˆ2/2

148
Q

what is the formula for gravitational potential energy

A

gpe = mass x gravitational field x change in height

149
Q

basically, what is work done

A

energy transferred

150
Q

what is the formula for work

A

w = fd

151
Q

what is power

A

rate of energy transfer

152
Q

what is the formula for power

A

p = energy / time

153
Q

formula for momentum

A

mass x velocity

154
Q

law of conservation of momentum

A

In any collision, the total momentum before and after the collision is
the same.

155
Q

impulse =

A

mvinitial−mvfinal

156
Q

what is impulse

A

change in momentum of a system

157
Q

force in terms of momentum formula

A

F=change in momentum/change in time
=Δp/Δt