The Eye Flashcards
1
Q
A
2
Q
A
3
Q
What is the difference between scalar and vector quantities?
A
Scalar quantities have magnitude only. Vector quantities have magnitude and an associated direction.
4
Q
What are examples of contact forces?
A
- Friction * Air resistance * Tension * Normal contact force
5
Q
What are examples of non-contact forces?
A
- Gravitational force * Electrostatic force * Magnetic force
6
Q
What is the definition of weight?
A
Weight is the force acting on an object due to gravity.
7
Q
What is the equation for calculating the weight of an object?
A
weight = mass x gravitational field strength
8
Q
What units are used to measure weight?
A
Newtons (N)
9
Q
What is the relationship between weight and mass?
A
The weight of an object and the mass of an object are directly proportional.
10
Q
What is the definition of work done?
A
Work done is when a force causes an object to move through a distance.
11
Q
What is the equation for work done by a force?
A
work done = force x distance
12
Q
Define elastic deformation.
A
Elastic deformation occurs when an object returns to its original shape and size after the forces are removed.
13
Q
What is Hooke’s Law?
A
The extension of an elastic object is directly proportional to the force applied, provided the limit of proportionality is not exceeded.
14
Q
What is the equation relating force, spring constant, and extension?
A
force = spring constant x extension
15
Q
What is the standard Physics definition of a joule?
A
One joule of work is done when a force of one newton causes a displacement of one metre.
16
Q
What happens to the energy stores when work is done on an object?
A
The energy stores change, for example, an increase in gravitational potential energy or thermal energy.
17
Q
What is meant by the term ‘resultant force’?
A
A resultant force is a single force that has the same effect as all the original forces acting together.
18
Q
Fill in the blank: The force acting on an object due to gravity is known as _______.
A
weight
19
Q
True or False: A single force can be resolved into two components acting at right angles to each other.
A
True
20
Q
What must be true for elastic potential energy to be stored in a spring?
A
The limit of proportionality must not be exceeded.
21
Q
What factors can affect the amount of force required to move an object?
A
- Surface type * Lubrication * Weight of the object
22
Q
How can you measure the size of a force?
A
Using a Newtonmeter.
23
Q
What is the purpose of a free body diagram?
A
To show the magnitude and direction of the forces acting on an object.
24
Q
What is the significance of the limit of proportionality in elasticity?
A
It is the point beyond which an elastic material will not return to its original shape.
25
What happens during inelastic deformation?
An object does not return to its original shape after the forces have been removed.
26
What are the units of force?
Newtons (N)
27
What is the work done in stretching a spring?
A force that stretches (or compresses) a spring does work and elastic potential energy is stored in the spring.
## Footnote
The work done on the spring and the elastic potential energy stored are equal, provided the spring does not exceed the limit of proportionality.
28
What is the equation for calculating elastic potential energy stored in a spring?
Ee = 1/2 k e^2
## Footnote
Where Ee is elastic potential energy in joules, k is the spring constant in N/m, and e is the extension in metres.
29
What is the limit of proportionality in relation to springs?
The limit of proportionality is the point beyond which the spring does not obey Hooke's law and does not return to its original length when the force is removed.
## Footnote
Beyond this limit, the relationship between force and extension becomes non-linear.
30
Define the moment of a force.
The turning effect of a force is called the moment of the force.
## Footnote
It is calculated using the equation: Moment (M) = Force (F) x Distance (d).
31
What equation should be known for calculating the moment of a force?
M = F x d
## Footnote
Where M is the moment in Nm, F is the force in N, and d is the perpendicular distance from the pivot in m.
32
What happens when an object is balanced in terms of moments?
The total clockwise moment about a pivot equals the total anticlockwise moment about that pivot.
33
How do simple gears function?
Simple gears transmit rotational effects of forces and can act as force multipliers.
34
What is the relationship between pressure and area in fluids?
Pressure is defined as force normal to a surface divided by the area of that surface: p = F/A.
## Footnote
Where p is pressure in pascals, F is force in newtons, and A is area in m².
35
How does fluid pressure change with depth?
In a liquid, pressure increases with the height of the column of liquid above a point and with the density of the liquid.
36
What is upthrust?
Upthrust is the resultant upward force on a submerged object due to greater pressure on the bottom surface than on the top surface.
37
Explain what happens to an object that is less dense than the surrounding liquid.
It displaces a volume of liquid equal to its own weight and floats.
38
What occurs when an object sinks in a liquid?
An object sinks when its weight is greater than the upthrust.
39
How does atmospheric pressure change with height?
Atmospheric pressure decreases with an increase in height due to fewer air molecules above a surface.
40
Define distance.
Distance is how far an object moves and is a scalar quantity.
41
Define displacement.
Displacement is the distance an object moves in a straight line from the start point to the finish point, including direction, making it a vector quantity.
42
What is speed?
Speed is the distance traveled per unit of time and is a scalar quantity.
43
What is the equation for calculating distance traveled at constant speed?
Distance (s) = Speed (v) x Time (t)
## Footnote
Where s is in meters, v is in meters per second, and t is in seconds.
44
What is the definition of velocity?
Velocity is the speed of an object in a given direction and is a vector quantity.
45
Why does an object moving in a circle have a changing velocity?
Because the direction of the object is continually changing, even if the speed remains constant.
46
What happens to the average velocity of an object around a circular track?
The average velocity is 0 m/s due to equal displacements in opposite directions.
47
Define velocity.
Velocity is a vector quantity that refers to the rate at which an object changes its position, including both speed and direction.
48
Explain why velocity is a vector quantity rather than a scalar quantity.
Velocity is a vector quantity because it has both magnitude (speed) and direction, while scalar quantities only have magnitude.
49
Explain why an object travelling around a circular track may have a constant speed but a constantly varying velocity.
An object on a circular track maintains constant speed, but its direction is continuously changing, resulting in a changing velocity.
50
Show that the average velocity of an object around a circular track is 0 m/s.
The average velocity is 0 m/s because the displacement is zero over one complete revolution, returning to the starting point.
51
Why is direction important when looking at collisions?
Direction is important in collisions as it determines the impact force and the resulting motion of the colliding objects.
52
Does a vehicle with a negative velocity mean that the vehicle is reversing?
Yes, a negative velocity indicates that the vehicle is moving in the opposite direction to the defined positive direction.
53
When an object moves round a track at a steady speed why is the average velocity 0 m/s?
The average velocity is 0 m/s because the total displacement is zero after completing a full loop.
54
How can the speed of an object be calculated from a distance-time graph?
The speed of an object can be calculated by determining the gradient of the distance-time graph.
55
What do the gradients of different lines on a distance-time graph represent?
The gradients represent the speeds of the objects; steeper lines indicate higher speeds.
56
What is the equation for acceleration?
The equation for acceleration is: acceleration = change in velocity / time taken.
57
Define acceleration.
Acceleration is the rate of change of velocity of an object.
58
If an object slows down, what is this process called?
This process is called deceleration.
59
What is Newton's First Law?
Newton's First Law states that an object will remain at rest or in uniform motion unless acted upon by a resultant force.
60
State the equation for Newton's Second Law.
F = m * a, where F is the resultant force, m is mass, and a is acceleration.
61
What is Newton's Third Law?
Newton's Third Law states that for every action, there is an equal and opposite reaction.
62
Define thinking distance.
Thinking distance is the distance a vehicle travels during the driver's reaction time.
63
Define braking distance.
Braking distance is the distance a vehicle travels while coming to a stop after the brakes are applied.
64
Define stopping distance.
Stopping distance is the sum of thinking distance and braking distance.
65
What factors can affect a driver's reaction time?
Factors include tiredness, drugs, alcohol, and distractions.
66
What happens to the forces acting on a skydiver at terminal velocity?
At terminal velocity, the driving forces equal the resistive forces, resulting in no acceleration.
67
How does the speed of a parachute fall depend on its size?
The size of the parachute affects air resistance; larger parachutes create more drag, slowing the fall.
68
What is terminal velocity?
Terminal velocity is the constant speed that a freely falling object eventually reaches when the resistance of the medium prevents further acceleration.
69
What does the area under a velocity-time graph represent?
The area under a velocity-time graph represents the distance travelled by the object.
70
Explain how to calculate acceleration from a velocity-time graph.
Acceleration can be calculated from the gradient of the velocity-time graph.
71
What factors affect the deceleration of a vehicle?
Factors include the mass of the vehicle, the braking force applied, and road conditions.
72
What is the typical range for human reaction times?
Typical reaction times range from 0.2s to 0.9s.
73
Why do heavier vehicles have greater stopping distances?
Heavier vehicles require more force to stop, resulting in longer stopping distances.
74
What is the relationship between speed and stopping distance?
For a given braking force, greater speed results in a greater stopping distance.
75
How can we experimentally investigate the acceleration of a trolley?
We can use light gates or ticker tape to measure the acceleration of a trolley as mass or driving force changes.
76
What is inertia?
Inertia is the tendency of an object to resist changes in its state of motion.
77
How does using a mobile phone while driving affect reaction time?
It increases reaction time due to distractions
## Footnote
Distractions can lead to delayed responses in critical driving situations.
78
What are three factors that can affect a person's reaction time?
* Drugs
* Distractions
* Tiredness
## Footnote
Each of these factors can significantly impair cognitive function and response speed.
79
What can be done to encourage motorists regarding mobile phone use?
Create a leaflet to encourage motorists to switch off mobile phones before driving
## Footnote
The leaflet could emphasize the dangers of distracted driving.
80
What factors affect the braking distance of a vehicle?
* Adverse road conditions
* Weather conditions
* Poor vehicle condition
## Footnote
These factors can significantly increase the distance required to stop a vehicle.
81
How do icy and wet roads affect braking distance?
They increase the braking distance of a vehicle
## Footnote
Reduced friction on slippery surfaces makes it harder to stop quickly.
82
What is the relationship between speed and braking distance?
The greater the speed, the greater the braking distance needed
## Footnote
This is due to the increased kinetic energy that needs to be dissipated.
83
What energy transfer occurs when a vehicle stops?
Work done by the friction force reduces the kinetic energy
## Footnote
The temperature of the brakes increases as they absorb energy.
84
What happens to brake pads when stopping from high speed?
They can overheat and warp
## Footnote
High speeds generate more heat due to increased friction.
85
What is momentum?
Momentum is defined as the product of mass and velocity
## Footnote
It is a vector quantity and is measured in kilograms meter per second (kg m/s).
86
What is the principle of conservation of momentum?
In a closed system, the total momentum before an event equals the total momentum after the event
## Footnote
This principle applies to collisions and explosions.
87
What is the equation for momentum?
p = m × v
## Footnote
Where p is momentum, m is mass, and v is velocity.
88
What is the effect of doubling the speed of a vehicle on its braking distance?
It increases the braking distance significantly
## Footnote
This is due to the square relationship between speed and stopping distance.
89
Why might the rims of bicycle wheels get hot when going down steep hills?
Due to friction generated by braking
## Footnote
Increased friction leads to heat generation in the braking system.
90
How does a force relate to momentum?
Force is equal to the rate of change of momentum
## Footnote
This is expressed mathematically as F = Δp/Δt.
91
What safety features help reduce injuries in a collision?
* Air bags
* Seat belts
* Crumple zones
## Footnote
These features work by increasing the time over which momentum changes, reducing forces experienced by occupants.
92
Why do motorcyclists face greater risk in collisions compared to car drivers?
They lack the protective structure of a vehicle
## Footnote
This increases their exposure to injury in the event of a crash.
93
What happens when a vehicle collides?
Momentum is conserved, but energy is transformed
## Footnote
Some kinetic energy is converted to heat, sound, and deformation.
94
Fill in the blank: The braking distance is affected by _______.
[adverse road conditions]
## Footnote
Other factors include vehicle condition and driver reaction time.
95
True or False: A heavier vehicle will have a shorter braking distance.
False
## Footnote
Heavier vehicles require longer distances to stop due to increased momentum.
