AQA P2 Physics GCSE - Key points

HideShow resource information
  • Created by: chaitz
  • Created on: 11-06-13 18:40
Preview of AQA P2 Physics GCSE - Key points

First 436 words of the document:

AQA Physics Unit 2 ­ Key Points
1.1 Distance Time Graphs
The distance-time graph for any object that is
- Stationary is a horizontal line
- Moving at a constant speed is a straight line that slopes upwards
The gradient of a distance-time graph for an object represents the object's speed.
Speed in metres per second, m/s =
distance travelled in metres, m
time taken in seconds, s
1.2 Velocity and acceleration
Velocity is speed in a given direction
Acceleration is change of velocity per second. The unit of acceleration is the metre per
second squared (m/s)
Acceleration = change of velocity
time taken
Deceleration is the change of velocity per second when an object slows down.
1.3 More about velocity-time graphs
If a velocity-time graph is a horizontal line, the acceleration is zero.
The gradient of a line on a velocity-time graph represents acceleration.
The area under the line on a velocity-time graph represents distance travelled (higher)
1.4 Using graphs
The speed of an object is given by the gradient of the line on its distance-time graph. (higher)
The acceleration of an object is given by the gradient of the line on its velocity-time graph.
The distance travelled by an object is given by the area under the line of its velocity-time graph.
2.1 Forces between objects
A force can change the shape of an object or change its motion or its state of rest.
The unit of force is the newton (N).
When two objects interact, they always exert equal and opposite forces on each other.
2.2 Resultant force
The resultant force is a single force that has the same effect as all the forces acting on an
If the resultant force on an object is zero, the object stays at rest or at constant velocity. If
the resultant force on an object is not zero, the velocity of the object will change.
If two forces act on an object along the same line, the resultant force is:
1. their sum if the forces act in the same direction
2. their difference if the forces act in opposite directions
2.3 Force and acceleration
The bigger the resultant force on an object is, the greater its acceleration is.
The greater the mass of an object is, the smaller its acceleration is for a given force.
Resultant force (newtons, N) = mass (kilograms) X acceleration (metres/second2)

Other pages in this set

Page 2

Preview of page 2

Here's a taster:

On the road
Friction and air resistance oppose the driving force of a car.
The stopping distance of a car depends on the thinking distance and the braking distance.
High speed, poor weather conditions and poor maintenance all increase the braking
distance. Poor reaction time and high speed both increase the thinking distance.
2.5 Falling objects
The weight of an object is the force of gravity on it. Its mass is the quantity of matter in it.…read more

Page 3

Preview of page 3

Here's a taster:

Momentum is conserved whenever objects interact, provided the objects are in a closed
system so that no external forces act on them.
3.5 Explosions
Momentum is mass x velocity and velocity is speed in a given direction.
When two objects push each other apart, they move apart:
with different speeds if they have unequal masses
with equal and opposite momentum so their total momentum is zero.
3.…read more

Page 4

Preview of page 4

Here's a taster:

Thermistor: resistance decreases if its temperature increases.
LDR: resistance decreases if the light intensity on it increases.
4.5 Series circuits
For components in series:
the current is the same in each component
adding the potential differences gives the total potential difference.
Adding the resistances gives the total resistance of resistors in series.
For cells in series, acting in the same direction, the total potential difference is the sum of
their individual potential differences.
4.…read more

Page 5

Preview of page 5

Here's a taster:

A mains appliance with a plastic case does not need to be earthed because plastic is an
insulator and cannot become live.
5.4 Electrical power and potential difference
The power supplied to a device is the energy transferred to it each second.
Electrical power supplied (watts) = current (amperes)
potential difference (volts)
Correct rating (in amperes) for a fuse = electrical power (watts)
potential difference (volts)
5.5 Electrical energy and charge
An electric current is the rate of flow of charge.…read more

Page 6

Preview of page 6

Here's a taster:

2 in the nucleus changes
neutrons into a proton
Particle emitted
2 protons and 2 neutrons
electron is created in the nucleus
as an particle and instantly emitted
Equation (higher)
A A-4 4 A A 0
Z X Z-2 Y + 2 Z X Z+1Y + -1
6.4 More about alpha, beta and gamma radiation
radiation is stopped by paper, has a range of a few centimetres in air and consists of
particles, each composed of two protons and two neutrons.…read more

Page 7

Preview of page 7

Here's a taster:

Energy is released when two light nuclei are fused together. Nuclear fusion in the Sun's
core releases energy.
A fusion reactor needs to be at a very high temperature before nuclear fusion can take place.
The nuclei to be fused are difficult to contain.
7.3 Nuclear issues
Radon gas is an -emitting isotope that seeps into houses in certain areas through the
There are thousands of fission reactors safely in use in the world.…read more


No comments have yet been made

Similar Physics resources:

See all Physics resources »See all resources »