# P3.4 Motion of particles Flashcards Preview

## Physics extension edexcel > P3.4 Motion of particles > Flashcards

Flashcards in P3.4 Motion of particles Deck (52)
1
Q

What is particle physics?

A

The study of subatomic and fundamental constituents of matter

2
Q

What are sub-atomic particles?

A

Particles smaller than atoms

3
Q

What are fundamental particles?

A

Particles that cannot be broken down into smaller units

4
Q

What particles are thought to be fundamental?

A

Quarks, anti-quarks, electrons and positrons

5
Q

How do scientists test new theories and models in particle physics?

A

They repeat experiments and critically evaluate the work published in science journals

6
Q

What is the LHC?

A

A particle accelerator

7
Q

Why is a particle accelerator used?

A

To collide particles at high energies to break them down into smaller ones

8
Q

What does circular motion require to keep moving in a circle?

A

A centripetal force

9
Q

What is a resultant force?

A

The total force from two or more forces acting on a single object

10
Q

How do you find the resultant force?

A

By adding the forces together while taking into account their direction

11
Q

What is a centripetal force?

A

A resultant force acting inwards along the radius

12
Q

What happens when an object travelling in a circular motion loses its centripetal force?

A

It travels in a straight line at a tangent to the circular path it was following

13
Q

What provides a centripetal force?

A

Tension

14
Q

Why is an object moving in circular motion accelerating even though the speed doesn’t change?

A

Because it is constantly changing direction

15
Q

What are cyclotrons?

A

Particle generators which bend moving charged particles into circular or spiral paths

16
Q

What produces the centripetal force required in a cyclotron?

A

A constant magnetic field applied at right angles to the particles motion

17
Q

What are the magnetic field regions in a cyclotron shaped as?

A

D-shaped

18
Q

What does the voltage in a cyclotron do?

A

Accelerate the charged particles

19
Q

Where is the voltage placed in a cyclotron?

A

Across a gap between the two D-shaped magnetic field regions

20
Q

What happens to the path of particles in a cyclotron as their speed increases?

A

It spirals outwards

21
Q

What happens once particles leave a cyclotron?

A

They travel in a straight line towards a specific target

22
Q

What happens when a high-energy proton collides with a stable element?

A

The nucleus can change into an unstable nucleus of a different element

23
Q

A

An unstable isotope that emits radiation

24
Q

What produces the short-lived isotopes used in PET scanners?

A

Small cyclotrons

25
Q

What type of collision does a ball dropped on the ground undergo?

A

Inelastic collision

26
Q

What is inelastic collision?

A

A collision where kinetic energy is not conserved

27
Q

What can kinetic energy in an inelastic collision be transferred as?

A

Heat or sound energy

28
Q

What is kinetic energy?

A

Movement energy

29
Q

Why does a ball not rebound to the same height after it’s been dropped?

A

Because kinetic energy has been transferred so it’s not the same as before

30
Q

What does LHC stand for?

A

31
Q

What is the formula for calculating momentum?

A
```p = mv
Momentum = mass x velocity```
32
Q

What is momentum?

A

A measure of the strength of movement

33
Q

What happens to momentum in all collisions?

A

It is conserved

34
Q

What happens to kinetic energy in an elastic collision?

A

It is conserved

35
Q

What is a vector?

A

Something that has both a size and a direction

36
Q

What type of value for momentum will an object moving backwards or to the left have?

A

Negative

37
Q

What is momentum measured in?

A

Kg m/s

38
Q

What is anti-matter?

A

Matter that has particles of the same mass and properties as their counterparts but opposite electrical charges

39
Q

What is the anti-matter of an electron?

A

A positron

40
Q

What happens when an electron and positron collide?

A

Total annihilation of the particles and the production of two gamma rays that move in opposite directions

41
Q

What do the basic conservation laws of physics apply to?

A

Mass, momentum and energy

42
Q

What is mass-energy equivalence?

A

The idea that destroyed mass can be converted into an equivalent amount of energy in order to obey conservation laws

43
Q

Who came up with the idea of mass-energy equivalence?

A

Einstein

44
Q

What is the formula for calculating the energy of a system from something that uses mass-energy equivalence?

A

E = mc^2

Energy of a system = mass x the speed of light squared

45
Q

What is the speed of light?

A

3 x 10^8 ms^-1

46
Q

What is the mass of an electron?

A

9 x 10^-31 kg

47
Q

What is the energy equivalent of the mass of an electron?

A

8 x 10^-14 J

48
Q

What is the total amount of energy released from a positron-electron annihilation?

A

1.6 x 10^-13

49
Q

What does PET scanner stand for?

A

Positron emission tomography scanner

50
Q

A

Positrons

51
Q

How are gamma rays produced in a PET scanner?

A

From the collision of positrons from the tracer and electrons from the scanner

52
Q

How does a PET scanner locate where a tracer has come from?

A

Through triangulation; it detects the two gamma rays emitted in opposite directions and can calculate where it came from