2a) Motion, Energy and Electricity Flashcards

0
Q

What does the gradient represent in a distance-time graph and a velocity-time graph?

A

In a distance-time graph, gradient means speed

In a velocity-time graph, gradient means acceleration

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1
Q

Define the difference between speed and velocity

A

Speed is how fast you’re travelling

Velocity is speed in a direction or with a vector

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2
Q

What is gravity?

A

The force of attraction between all masses

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3
Q

How do you work out weight using mass and gravitational field strength?

A

W=mxg

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4
Q

What is the resultant force?

A

Overall force of an object

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5
Q

If there is a resultant force acting on an object, what will happen to the object?

A

Object will change it’s state of rest or motion or change its velocity (acceleration)

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6
Q

What happens is the resultant force on a stationary object is zero?

A

Object will remain stationary

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7
Q

If there is no resultant force on a moving object, what will happen?

A

Object will keep moving in the same direction at the same velocity
No change in velocity

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8
Q

When two objects interact, the forces they exert on each other are…..?

A

Equal and opposite

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9
Q

If an object has no force propelling it along, why would it slow down and stop?

A

Friction acts in the opposite direction to movement

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10
Q

How can you reduce drag or air resistance by changing the shape of a vehicle?

A

Streamlined

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11
Q

What happens to drag as speed increases?

A

Drag increases

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12
Q

What does the terminal velocity of falling objects depend on?

A

Their shape and area

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13
Q

What is stopping distance?

A

Distance covered in the time between the driver spotting a hazard and the vehicle coming to a complete stop
Sum of thinking distance and breaking distance

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14
Q

What things affect thinking distance?

A

How fast you’re going - faster speed = further distance
Brain state - affected by tiredness, drugs, alcohol, careless attitude
Bad visibility and distractions

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15
Q

What is thinking distance?

A

The distance the vehicle travels during the driver’s reaction time

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16
Q

What is braking distance?

A

The distance a car travels under the braking force

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17
Q

What is braking force affected by?

A

How fast you’re travelling - faster speed = further distance
Quality of brakes
Thickness of tyres - thicker tyres = better braking distance
Grip - affecting road surface, weather, tyres

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18
Q

What happens regarding forces when a force moves an object through a distance?

A

Energy is transferred

Work is done

19
Q

How do you calculate work done?

A

Force x distance

20
Q

What is gravitational potential energy?

A

Energy that an object has because of its vertical position in a gravitational field

21
Q

What two things does kinetic energy depend on?

A

Mass - more it weighs, faster speed, bigger kinetic energy

Speed - faster, bigger kinetic energy

22
Q

What does the conservation of energy state?

A

Energy can never be created it destroyed only converted into different forms

23
Q

When something falls, what is it’s potential energy converted into?

A

Kinetic energy

24
What is an elastic object?
Any object that can go back to its original shape after a force has been removed
25
What is extension measured in?
Metres
26
What is elastic potential energy?
Potential energy stores in an elastic object which has had work done to change it's shape
27
What is power?
The rate of doing work or the time taken for energy to be transferred
28
What is power measured in?
Watts (joules per second)
29
What is current?
Rate of flow of electric charge around a circuit
30
What is potential difference?
The driving force that pushes the current round | The work done (energy transferred) per coulomb of charge
31
What is resistance?
Anything in a circuit which slows down the current
32
What happens to resistance when temperature increases?
Resistance increases
33
What is a diode made from?
Semiconductor material such as silicon
34
What is a diode for?
Used to regulate potential difference in circuits Lets current flow freely in one direction but not in the other High resistance in reverse direction
35
Why are LEDs better than normal lighting?
They use a much smaller current
36
What does LED and LDR stand for)
Light Emitting Diode | Light Dependant Resistor
37
What is an LDR
Resistor that is dependant on the intensity of light Bright light - resistance falls Darkness - high resistance
38
What is a thermistor?
Temperature dependant resistor Hot - resistance falls Cold - high resistance
39
In what type of circuit is the potential difference shared across the components?
Series circuit V = v1 + v2 + .....
40
In what type of circuit is the current the same everywhere?
Series circuit
41
How do you work out the resistance in a series circuit?
Total resistance = sum of all the resistances
42
If you add more bulbs to a series circuit what will happen to their light?
Light up less brightly than before | Because p.d is shared in series circuits
43
In what type of circuit is the potential difference the same across all components?
Parallel circuits
44
When something falls, what happens to it's potential energy?
Converted into kinetic energy Further it falls - faster it goes
45
What is the limit of proportionality?
Maximum force that the elastic object can take and still extend proportionally