P2 b Flashcards

(54 cards)

1
Q

What affects your braking distance

A

Your thinking and braking distance

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

What affects your thinking time

A

Your reaction time and how fast your going the faster you go the more ground will be covered before reactions take place

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

What factors affect braking distance

A

How fast your going, the mass of the vehicle a heavier vehicle takes longer to stop. How good your brakes are and how good the grip of the tyres is .

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

What affects a tires grip

A

Road surface weather conditions and tyre conditions

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

How do you calculate an objects momentum

A

Mass x Velocity

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

What happens to momentum after an incident

A

The same momentum is present the total momentum after is the same as before

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

What happens when a force acts on an object

A

It causes a change in momentum

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

How can you calculate the force

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

What does a larger force mean

A

A faster change of momentum

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

Why do cars have airbags and such?

A

To extend the time the change in momentum occurs over in order to reduce the force acting on the body

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

What are examples of safety mechanisms in cars

A

Crumple zones, these increase the time taken for the car to stop
Seat belts stretch slightly increasing the time for the wearer to stop
Air bags slow you down more gradually

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is work

A

It is when a force moves an object and energy is transferred this means work is done

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is power

A

Is the rate of doing work it is calculated by the work done divided by a given time

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

What is power measured in

A

Watts or joules 1 watt = 1 joule of energy transferred per second
Watts are the same as joules per second

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

What do all moving objects have

A

Kinetic energy

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

How to calculate kinetic energy

A

1/2 x mass x velocity squared

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

What is gravitational potential energy

A

It is the potential energy an object holds mainly affected by its height as that can vary

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

How do you calculate G.P.E

A

Mass x gravitational field strength x height

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

What is the principle of conservation of energy

A

Energy can never be created nor destroyed.

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

When an object falls the kinetic energy gained is equal to

A

The gravitational potential energy lost

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

What is a problem assuming that kinetic energy gained = gravitational potential energy lost

A

It doesn’t account for other factors such as heat or sound

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

What happens to unstable nuclei

A

They decay this is random

23
Q

What are the three types of ionising radiation

A

Alpha, short range, weak penetrating
Beta, medium range, medium penetrating
Gamma, long range, highly penetrating

24
Q

What does ionising radiation mean

A

They cause the ionising of atoms or loosing of an electron

25
How does alpha radiation ionise
It has a large positive charge when it passes close to an atom it pulls an negatively charged electron out of orbit
26
How does beta radiation ionise
It is negatively charged so pushes electrons out of orbit
27
How is gamma radiation ionising
The transfer energy to electrons if the electron gains enough energy it can break free
28
What are alpha particles
Helium nuclei | Big heavy slow moving positive charge. Paper stops it
29
What are beta particles
Electrons emitted from a nucleus | Fast and small negative charge, moderately ionising but stopped by aluminium .
30
What happens when a beta particle is emitted
A neutron turns into a proton in the nucleus
31
What is a gamma rays
Electromagnetic radiation weakly ionising only stopped by thick lead
32
What is nuclear fission
The splitting up of atoms
33
How to start a chain reaction
A slow moving neutron is fired at an isotope of uranium. Th neutron is absorbed by the nucleus it becomes unstable and causes it to split
34
How are chain reCtions controlled
Placed in a moderator to slow down the neutrons I.e water this creates a steady rate of nuclear fission. Control rods made of boron limit fission by absorbing excess neutrons
35
What is nuclear fusion
The joining of two smaller nuclei to make a larger one. This usually happens inside stars and requires extreme pressure and heat
36
Why doesn't nuclear fusion happen at lower pressures and temperatures
Due to electrostatic repulsion of protons
37
Why is a fusion reactor hard to build
Most materials are vaporised at the temperature so you have to contain hot hydrogen in a magnetic field instead of physical container
38
What is background radiation
Low level radiation that around all the time
39
Where does background radiation come from
It comes from natural unstable isotopes radiation from space know as cosmic rays and radiation due to human activity I.e nuclear fallout
40
What is half life
The time taken for half the undeclared nuclei to decay
41
What is the radioactivity of an isotope measured in
Becquerel s 1Bq is 1 decay per second
42
How to measure half life from a graph
Measure the background radiation count first and subtract it from the isotope count. Then divide that by two and find this point on the graph across and down to time
43
What are some uses of radioactive decay
Smoke detectors Sterilisation of food Trackers and thickness gauges Treating cancer
44
How is alpha radiation used in smoke debtors
A weak source of alpha is placed in a smoke detector close to two electrodes. The source causes ionisation and a current flows. If there is a fire then the smoke will absorb the radiation causing the current to stop and the alarm to trigger
45
How is food sterilised
Exposing it to high doses of gamma rays will kill all microbes. This is called irradiation this can be used for medical equipment too
46
How does a thickness gauge work
Beta radiation is used in thickness control. You fire beta at the object and place a detector on the other. When the amount of beta detected changes the thickness must of changed. This source must half a long half life.
47
What can ionising radiation cause
Tissue damage and cell mutation
48
What do lower doses of radiation do
Minor damage without killing the cell leading to mutant cells which divide uncontrollably
49
What effect do higher doses of radiation have
They tend to kill cells this causes radiation sickness
50
How can you minimise exposure to radioactive isotopes in the lab
Never allow skin contact and handle with tongs, keep the source at arms length, keep it pointing away and don't look at it. But the source in a lead box.
51
What is a problem with nuclear fission reactor s
They create radioactive waste products, they can't be recycled and usually have very long half lives.
52
How do plants deal with radioactive waste
By vitrification , thy melt the waste with other materials to form a type of glass it is then sealed in steel canisters and buried . The general idea is to hide it in a place where the materials around it absorb the radioactive waste before it reaches the surface
53
What are the negatives of nuclear power
Public perception is negative they see it as dangerous. Some believe nuclear waste can never be disposed of safely there is always a risk of leaks. Nuclear power carries the risk of major incidents such as Chernobyl . The building of the plant is extremely expensive and dismantling safely takes decades
54
What are the pros of nuclear power
It is actually a pretty safe way of generating electricity . It is reliable and reduces the need for fossil fuels. It doesn't real ease greenhouse gases like fossil fuels such as carbon dioxide . Huge amounts of energy can be generated from a relatively small amount of nuclear material . Fuel is pretty cheap and readily available