1
Q
Scalar quantities definition
A
- Have magnitude (size) only
They do NOT include direction
2
Q
Vector quantities definition
A
Has BOTH magnitude and a direction
3
Q
Examples of a scalar quantity
(6)
A
- Mass
- Temperature
- Speed
- Energy
- Distance
- time
4
Q
Examples of a vector quantity
(7)
A
- Displacement
- Weight
- Force
- Velocity
- Acceleration
- Momentum
- gravity
5
Q
Force definition
A
A push or pull that acts on an object due to the interaction with another object
All forces has both magnitude and a direction so it’s a vector quantity
6
Q
Unit for force
A
Newtons (N)
7
Q
Contact forces
A
- Friction
- Air resistance
- Tension
- Normal force
8
Q
Non-contact forces
A
- Gravity
- Magnetism
- Electrostatic force
9
Q
Weight definition
A
Weight is the force acting on an object due to gravity
The weight of an object is directly proportional to the mass of the object
* Weight ∝ mass
10
Q
Unit for weight
A
Newtons (N)
11
Q
We can determine an object’s weight by using a…
A
- Calibrated spring balance
- This is also called a newton meter
12
Q
Centre of mass definition
A
the point at which the mass of an object is balanced in all directions.
13
Q
Weight and gravitational field
A
- The gravitational field depend where you are (planet)
- This could change the weight since, Weight = mass x gravitational field
14
Q
Gravitational field definition
A
Is a measure of the force of gravity in a particular location
15
Q
Resultant force definition
A
the overall force acting on an object when all the individual forces are combined.
Larger force - smaller force = resultant force
16
Q
unit for resultant force
A
newton (N)
17
Q
Altitude definition
A
the height of an object or point above sea level or ground level.
Constant altitude means that the up and down forces are equal
18
Q
Unit of work done
A
Joules (J)
19
Q
Elastic deformation definition
A
when a material returns to its original shape after the force causing the deformation is removed.
20
Q
Inelastic deformation definition
A
when a material does not return to its original shape after the force is removed — it is permanently deformed.
e.g. certain polymers
21
Q
Unit of spring constant
A
- K
- Newtons per metre (N/m)
22
Q
Unit for compression
A
- E
- Metres (m)
23
Q
Work done and elastic potential energy
A
The work done is equal to the elastic potential energy
However that’s only true if the object is not inelastically deformed
24
Q
Normal walking speed
A
1.5 m/s
25
Running speed
3 m/s
26
Cycling speed
6 m/s
27
Car on main road speed
13 m/s
28
Fast train in the uk speed
50 m/s
29
Cruising aeroplane
250 m/s
30
Speed of sound in air
330 m/s
| Sound travels faster on warmer days than cooler ones
31
Velocity definition
Velocity is the speed of an object in a given direction.
| It's a vector quantity
## Footnote
It's answer is given as … e.g. velocity is 1.25 m/s south
32
Velocity in a car moving in a circle
If the object moves at a constant speed in a circle then it's velocity is constantly changing even though it's speed is constant
33
Acceleration definition
The acceleration of an object tells us the change in its velocity over a given time
34
Acceleration unit
- a
* m/s²
35
Notes
* The equation for when an object is accelerating at a constant rate then we can use this equation
v²-u² =2as
36
Terminal velocity
definition
the maximum velocity an object reaches when the resistance force (like air resistance) balances the weight, so the object stops accelerating.
## Footnote
Some objects experience a greater force of friction due to their shape so they will have a lower terminal velocity
37
Newtons 1st law definition
an object will stay at rest or move at a constant velocity unless acted on by a resultant force.
38
Newtons 2nd law definition
states that the force acting on an object is equal to its mass times its acceleration.
| ***F=ma***
39
Newtons 3rd law definition
Whenever two objects interact the forces they exert on each other are equal and opposite
## Footnote
Canoe
- A man is using a paddle to push the water
- At the same time, the water pushes back on the paddle
- This force is equal in magnitude but opposite in direction
40
Resistive force
a force that opposes motion
## Footnote
e.g.
* Friction
* air resistance
***In water***
* Water resistance
* drag
41
Inertia definition
the tendency of an object to resist changes in its motion (whether it's at rest or moving at a constant velocity).
## Footnote
Objects will stay still or keep the same motion unless you apply a resultant force
42
Inertial mass
the measure of how difficult it is to change the velocity of an object because of its mass.
* it's defined as the ration of the force needed to accelerate an object over the acceleration produced
## Footnote
An object with a large inertial mass will require a larger force to produce a given acceleration than an object with a smaller inertial mass
43
Stopping distance definition
the total distance a vehicle travels from the moment the driver spots a hazard to when the vehicle comes to a complete stop.
44
Thinking distance definition
the distance travelled during the driver’s reaction time, before braking starts.
45
Reaction time definition
the time between the driver seeing a hazard and applying the brakes.
46
Braking distance definition
the distance the vehicle travels after the brakes are applied until it stops.
47
Factors effecting the breaking distance
- Wet or icy conditions reduce the friction between the tyres and the road
- Worn out tires
* Worn out brakes
48
Factors effecting the thinking distance
- Being tired
- Alcohol
- Certain drugs
* Distraction
49
Factors effecting the reaction time
- Being tired
- Alcohol
- Certain drugs
* Distraction
50
Car calc
Stopping distance = thinking distance - braking distance
51
Permanent magnet definition
a material that produces its own magnetic field and keeps it without needing to be magnetised by an external source.
52
Induced magnet definition
a material that becomes magnetic only when placed in a magnetic field.
| It loses its magnetism when the magnetic field is removed.
53
South and north poles in magnets
Two same poles repel whilst opposite attracts
54
What are the 4 types of magnetic field
- Iron
- Steel
- Cobalt
* nickel
## Footnote
All can be made into both a permanents or induced magnet
55
Magnetic field definition
the region around a magnet where magnetic forces can be felt or where a magnetic material experiences a force.
56
Magnetic flux density
It is the strength of the magnetic field
57
Motor effects definition
Motor effect is when a current-carrying wire placed in a magnetic field experiences a force.
58
Magnetic flux density units
measured in tesla (T)
59
Transverse waves
waves where the oscillations are perpendicular to the direction of energy transfer.
* oscillations go up and down
* direction of energy transfer is sideways
## Footnote
Not all transverse waves require a medium to travel in (e.g. air, liquid or a solid)
60
Transverse waves examples
* Light
* Water waves/ripples
* Radio waves
* Microwaves
* Seismic S-waves
61
Longitudinal waves
waves where the oscillations are parallel to the direction of energy transfer.
* oscillations goes side to side
* direction of energy transfer is sideways
## Footnote
All longitudinal waves require a medium to travel in (e.g. air, liquid or a solid)
62
Seismic waves
* Seismic P-waves are longitudinal.
* Seismic S-waves are transverse.
## Footnote
* P-waves travel through solids and liquids.
* S-waves only travel through solids.
63
Frequency unit
- f
- Hertz (Hz)
| 1Hz = 1 wave per second
64
Period definition
The time (in seconds) for one wave to pass a point
65
Period unit
seconds
66
Wave speed definition
The speed at which the wave moves through the medium
(ie the speed at which energy is transferred)
67
Wave speed unit
m/s
68
Wavelength unit
- λ (lambda)
* metre (m)
69
Amplitude definition
The amplitude of the wave is the maximum displacement of a point on a wave from its undisturbed
70
Wavelength definition
The distance from a point on one wave to the equivalent point on the next wave
71
Frequency definition
The number of waves passing a point each second
72
light
An example of an electromagnetic wave
73
electromagnetic wave definition
- transverse waves
That transfer energy from the source of the waves to an absorber
## Footnote
***Examples ***- a microwave oven
Microwaves transfer energy from the source (the oven) to the absorber (food)
***Another example ***
Light waves transfer energy from the source (the sun) to the absorber (solar panels on the space craft)
74
Electromagnetic waves travelling
- They do not need a medium to travel in
- That means that an electromagnetic wave can travel through a vacuum
(e.g. space)
- They all travel at the same speed in a vacuum
| 3x10(8)m/s
75
Wave front
An imaginary line that connects all the same points in a set of waves
## Footnote
Makes it easier to visualise lots of waves moving together
76
X rays and gamma rays
| bad
Can cause a mutation in gene which could lead to cancer as they can knock of atoms when they are absorbed
77
Conventional current
the direction that positive charge would flow in a circuit:
from the positive terminal to the negative terminal.
✅ Even though electrons actually flow the opposite way, we still use conventional current direction in diagrams and equations.
78
Alternating current definition
an electric current that reverses direction regularly.
physics GCSE
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