Motion, Forces And Conservation Of Energy Flashcards
1
Q
What is a vector quantity
A
A magnitude and a direction
2
Q
Give examples of vector quantities
A
Weight, momentum, force, velocity, displacement, acceleration etc.
3
Q
What is a scalar quantity
A
A magnitude and no direction
4
Q
Give examples of scalar quantities
A
Mass, distance, speed, energy, temperature, time etc.
5
Q
What is distance
A
How far an object has moved
6
Q
What is displacement
A
The distance and direction in a straight line from an object’s starting point to its finishing point
7
Q
What is speed
A
How fast you’re going with no regard to the direction
8
Q
What is velocity
A
Speed in a given direction
9
Q
What is the equation involving distance travelled, speed and time
A
d
——-
s x t
10
Q
What is the typical speed for walking
A
1.4 m/s
11
Q
What is the typical speed for running
A
3 m/s
12
Q
What is the typical speed for cycling
A
5.5 m/s
13
Q
What is the typical speed for cars in a built up area
A
13 m/s
14
Q
What is the typical speed for cars on a motorway
A
31 m/s
15
Q
What is the typical speed for trains
A
Up to 55 m/s
16
Q
What is the typical speed for aeroplanes
A
250 m/s
17
Q
What is the typical speed for ferries
A
15 m/s
18
Q
What is the typical wind speed
A
5-20 m/s
19
Q
What is the typical speed of sound in air
A
340 m/s
20
Q
What is acceleration
A
The change in velocity in a certain amount of time
21
Q
What is the equation for acceleration
A
a = (v - u)
———
t
22
Q
What does v stand for
A
Initial velocity
23
Q
What does u stand for
A
Final velocity
24
Q
What is constant acceleration also called
A
Uniform acceleration
25
What does the gradient on a distance time graph show
The speed of an object
26
What do the flat sections on a distance time graph show
Where it’s stopped
27
What does a steeper distance time graph mean
It’s going faster
28
What do curves in a distance time graph show
It’s acceleration
29
What does a curve getting steeper in a distance time graph show
It is speeding up
30
What does a levelling off curve in a distance time graph mean
It is slowing down
31
What is the equation for speed on a distance time graph
Speed = gradient = change in the vertical / change in the horizontal
32
What do flat sections in a velocity time graph represent
A steady speed
33
What does a steeper velocity time graph mean
The greater the acceleration or deceleration
34
What are uphill sections (/) in a velocity time graph
Acceleration
35
What are downhill sections (\) in a velocity time graph
Deceleration
36
What do curves mean in a velocity time graph
Changing acceleration
37
What is newton’s first law
If the resultant force on a stationary object is zero, the object will remain stationary. If the resultant force on a moving object is zero, it’ll just carry on moving at the same velocity
38
What does a non-zero resultant force produce
Acceleration or deceleration
39
What are the 5 forms of acceleration
Starting, stopping, speeding up, slowing down, changing direction
40
What is newton’s second law
The larger the resultant force acting on an object, the more the object accelerates - the force and the acceleration are directly proportional.
Acceleration is also inversely proportional to the mass of an object - so an object with a larger mass will accelerate less than one with a smaller mass
41
What is the formula to show Newton’s second law
F = m x a
42
What does F stand for
Resultant force
43
Why can large decelerations cause injuries
Because large deceleration requires a large force
44
What safety features in a car increase collision times
Crumple zones, seat belts, air bags
45
What is mass
The amount of ‘stuff’ in an object
46
What is weight
The force acting on an object due to gravity
47
What is weight measured in
Newtons
48
What is mass measured in
Kilograms
49
How is weight measured
With a newton meter
50
How is mass measured
With a mass balance
51
What is the formula for weight
Weight = mass x gravitational field strength
52
What is gravitational field strength measured in
N/kg
53
If an object is travelling in a circle, where does the resultant force act upon
Towards the centre of the circle
54
What is a centripetal force
The force that keeps something moving in a circle
55
What does an object inertial mass measure
How difficult it is to change the velocity of an object
56
What is newtons third law
When two objects interact, the forces they exert on each other are equal and opposite
57
What is the formula for Newton’s second law
F = ma
58
What is the formula for momentum
p = m x v
59
What does p stand for
Momentum
60
What is momentum measured in
Kg m/s
61
What is the equation for stopping distance
Stopping distance = thinking distance + braking distance
62
What is thinking distance
The distance the car travels in the driver’s reaction time
63
What is your reaction time increased by
Tiredness, alcohol, drugs, distractions
64
What is braking distance
The distance taken to stop once the brakes have been applied
65
What affects your braking distance
Speed
Mass of the car
Condition of the brakes
How much friction is between your tyres and the road
66
What are the 8 different types of energy
```
Kinetic
Thermal
Chemical
Gravitational potential
Elastic potential
Electrostatic
Magnetic
Nuclear
```
67
What is kinetic energy
The energy stored of a moving object
68
What is the formula for kinetic energy
Kinetic energy = 0.5 x mass x (speed)2
KE = 1/2 x m x v2
69
What is gravitational potential energy
The energy stored in an object when it is at any height above the earth’s surface
70
What is the formula for gravitational potential energy
GPE = m x g x h
71
What does g stand for
Gravitational field strength
72
What does conservation of energy mean
Energy is never created or destroyed
73
What is a closed system
A system (a collection of objects) that can be treated completely on its own, without any energy being exchanged to or from the surroundings
74
How do you make it a closed system
By increasing the number of things you treat as a part of it
75
What is thermal energy
Heat energy
76
What is chemical energy
The energy produced in a chemical reaction
77
What is elastic potential energy
The energy that occurs in things like springs and rubber bands etc.
78
What is electrostatic energy
The energy when two charges attract or rebel each other
79
What is magnetic energy
The energy when two magnets attract or repel each other
80
What is nuclear energy
The energy released from the atomic nuclei in nuclear reactions
81
What are the 4 main ways of energy transfers
Mechanically
Electrically
By heating
By radiation
82
What are mechanical energy transfers
Energy transferred when a force is acting on an object eg. Pushing, stretching, squashing
83
What are electrical energy transfers
Energy transferred when a charge is doing work eg. Charges moving round a circuit
84
What is energy transfer by heating
Energy transferred from a hotter object to a colder object eg. Heating a pan on a hob
85
What is energy transfer by radiation
Energy transferred by waves eg. Energy from the sun reaches the Earth by light
86
When is energy useful
When it is transferred from one store to a useful store
87
What is the conservation of energy principle
Total energy input = useful energy output + wasted energy
88
What is the formula for efficiency
Efficiency = useful energy transferred by device
———————————————-
Total energy supplied to device
89
What are 2 ways to reduce the amount of wasted energy
Lubrication
| Insulation
90
How does lubrication reduce the amount of wasted energy
It reduces the friction between objects’ when surfaces move
91
How does insulation reduce the amount of wasted energy
By heating
92
What are non-renewable energy resources
Fossil fuels and nuclear fuel
| They will run out
93
What are fossil fuels
Natural resources that form underground over millions of years that are typically burnt to provide energy
94
What are the 3 main fossil fuels
Coal
Oil
Gas
95
What do fossil fuels release into the atmosphere
Carbon dioxide
96
What does the release of sulfur dioxide cause
Acid rain
97
How can acid rain be reduced
By taking the sulfur out of the fossil before it is burned, or cleaning up the emissions
98
What are renewable energy resources
Energy resources which will never run out
99
What are the renewable energy resources
```
Bio-fuels
Wind
Solar
Hydro-electricity
Tides
```
100
What are biofuels
Renewable energy resources created from either plant products or animal dung
101
How do wind turbines work
Each wind turbine has a generator inside it so when wind rotates the blades, it turns the generator which produces electricity
102
What are the costs for wind turbines
Initially quite high but running costs are minimal
103
What are the problems of wind turbines
They only work when it’s windy so you can’t always supply electricity, or respond to high demand
104
How do solar panels work
They are made from materials which use energy transferred by light to create an electric current
105
What are the costs of solar energy
Initial costs are high but there are basically no running costs
106
What are the problems of solar panels
You can’t make solar power at night or increase production when there is a popular demand
107
How does hydro-electricity work
It involves flooding a valley by building a big dam. Rainwater is caught and allowed out through turbines
108
What are the problems of hydro-electricity
There is a big impact on the environment due to the flooding of the valley and a possible loss of habitat for some species
109
What is a big advantage of hydro-electricity
It can immediately respond to increased electricity demand as more water can be let out through the turbines, generating more electricity
110
What are the costs of hydro-electricity
Initially high, but there are minimal running costs
111
What are tidal barrages
Big dams built across river estuaries with turbines in them
112
How do tidal barrages work
As the tide comes in, it fills up the estuary. The water is then let out through the turbines at a controlled speed to generate electricity
113
What are the problems of tidal barrages
They affect boat access, can spoilt the view and they alter the habitat for wildlife
114
What are the costs for tidal barrages
Initially moderately high but there are no fuel costs and minimal running costs
