# Physics A2 Unit 4

• Created by: Lucy
• Created on: 05-09-13 19:42
What does the area under the Force-Time graph represent?
Impulse
1 of 25
Define the frequency of circular motion.
The frequency, f, is the number of complete revolutions per second (Hz)
2 of 25
Define the period of circular motion.
The period, T, is the time taken for a complete revolution (in seconds)
3 of 25
In which direction does the centripetal force act?
Towards the centre of the circle
4 of 25
Define Simple Harmonic Motion (2)
*An oscillation in which the acceleration of an object is directly proportional to its displacement from the midpoint, *and is directed towards the midpoint
5 of 25
What two factors are independent of the amplitude in SHM?
Frequency and Period
6 of 25
Explain why the motion of a ball bouncing off the ground is not SHM.
The acceleration of a falling bouncy ball is due to gravity. This acceleration is constant, so no SHM.
7 of 25
What are free oscillations?
Oscillations where there is no damping and no periodic force acting on the system so the amplitude of the oscillations is constant.
8 of 25
What are forced oscillations?
Oscillations of a system that is subjected to an external periodic force
9 of 25
Describe resonance
When a system is forced to vibrate at a frequency that's close to, or the same as its natural frequency and oscillates with a much larger than usual amplitude
10 of 25
Describe critical damping
Critical damping reduces the amplitude in the shortest possible time
11 of 25
Which direction do field lines go in?
From north to south
12 of 25
Describe how to use Fleming's left-hand rule
The First finger points in the direction of the uniform magnetic field. The second finger points in the direction of the conventional current. The thumb points in the direction of the force (in which motion takes place).
13 of 25
What is the magnetic field strength (flux density), B, defined as?
The force on one metre of wire carrying a current of one amp at right angles to the magnetic field.
14 of 25
What is magnetic field strength measured in?
teslas, T
15 of 25
What is a field line/ line of force?
This is a line followed by a small mass in a gravitational field (or a small positively charged object in an electric field or a free north pole in a magnetic field) acted on by no other forces that the forces due to the field.
16 of 25
This is where the field lines are straight and converge or diverge as if from a single point. The magnitude of g in a radial field decreases with increased distance from the centre.
17 of 25
What is a uniform field?
This is where the gravitational field strength is the same in magnitude and direction throughout the field. The field lines are therefore parallel to one another and equally spaced.
18 of 25
What is gravitational potential, V?
At a point in a gravitational field is the work done per unit mass to move a small object from infinity to that point.
19 of 25
What is a gravitational force?
An attractive force that acts equally on any two objects due to their mass.
20 of 25
What is gravitational field strength?
The force per unit mass on a small mass placed in the field.
21 of 25
What is gravitational potential energy?
at a point in a gravitational field is the work done to move a small object from infinity to that point.
22 of 25
What is equipotential?
A line or surface in a field along which the electric or gravitational potential is constant.
23 of 25
The potential gradient at a point in a gravitational field is the change of potential per metre at that point.
24 of 25
State the condition under which the equation F= BIl applies
It only applies when the magnetic field is directed at right angles to the current.
25 of 25

## Other cards in this set

### Card 2

#### Front

Define the frequency of circular motion.

#### Back

The frequency, f, is the number of complete revolutions per second (Hz)

### Card 3

#### Front

Define the period of circular motion.

#### Back ### Card 4

#### Front

In which direction does the centripetal force act?

#### Back ### Card 5

#### Front

Define Simple Harmonic Motion (2)

#### Back 