This document has 19 pages of detailed and well-written Physics Edexcel GCSE notes to a Level 9 standard. It includes diagrams, detailed explanations, specification points, etc. These notes are of an incredibly high quality.
1.3
For distance-time graphs, time on x-axis, distance on y-axis, gradient = speed
1.5
Describe experiments about the motion of everyday objects e.g. tennis ball or toy car
Say distance measuring over, flat or sloped surface, time it takes, variables, etc.
1.6
Acceleration = change in velocity / time taken
a = (v-u) / t
v = final velocity
u = initial velocity
1.7, 1.8, 1.9
For velocity-time graphs, time on x-axis, distance on y-axis, area under line = displacement, gradient =
acceleration (unlikely to be the same everywhere on the graph)
1.10
(final speed)2 = (initial speed)2 + (2 x acceleration x distance moved)
v2 = u2 + (2as)
1.19
Stopping distance (distance it takes to stop) = thinking distance (distance travelled between event and driver
reacting) + braking distance (distance travelled by vehicle while braking)
Thinking distance = speed x reaction time
1.20
Factors affecting vehicle stopping distance:
Icy or wet roads reduce grip on tyres
Gravel, mud or oil reduce grip on tyres
Worn tyres reduced grip on road
Worn brake pads reduce braking force
Mass of car deceleration is slower
Speed of car faster = longer stopping distance
Reaction time may be affected by intoxication, tiredness or being distracted
1.21
All masses fall with the same downwards acceleration due to gravity if the effect of air resistance is
ignored.
The acceleration due to gravity at
the earth’s surface friction is 10 m/s2 (or
9.81 m/s2 more friction precisely)
Terminal velocity:
weight weight weight
If the object is falling from As the speed increases Soon friction balances the
rest, there is no friction acting friction also increases. weight of the object, the
upon it initially. The resultant force on the object
unbalanced force is the The resultant force and the is zero.
The object no longer
weight of the object. acceleration decrease.
accelerates, it travels at a
constant speed called its
terminal velocity.
,The larger the area, the larger the air resistance
The larger the speed, the larger the air resistance
1.22
Springs
Set up the apparatus as shown in the diagram.
A single mass (0.1 kg, 100g) is attached to the spring, with a pointer
attached to the bottom, and the position of the spring is measured against
the ruler.
The mass ( in kg) and position (in cm) are recorded in a table.
A further mass is added, and the new position measured.
The above process continues until a total of 7 masses have been added.
The masses are then removed, and the entire process repeated again, until it has been carried out a
total of three times, and averages can then be taken.
Once measurements have been taken:
o The force on the spring can be found by multiplying the mass of the spring (in kg) by 10 N/kg
(the gravitational field strength).
o The extension of the spring can be found by subtracting the original position of the spring
from each of the subsequent positions.
Wires
A wire stretches by much less than a spring. In
order to measure its extension a long length of wire
is usually needed.
The apparatus should be set up as shown in the
diagram.
A single mass (0.1 kg) should be attached to the end of the wire and then the initial length of the
wire measured using a small pointer attached midway along the wire.
Masses are then added, one at a time, to the end of the wire and the new length measured and
recorded.
This is continued until the wire breaks.
The experiment can then be repeated, and averages taken.
Rubber bands
This experiment is essentially the same as the spring experiment, the sole difference being that
once all of the masses have been added, they should then be removed one at a time, and the
positions recorded as this is done.
(Rubber bands remain slightly extended after stretching, and so the readings taken whilst unloading the
band will be slightly longer than those taken whilst loading it).
1.23
A force extension graph shows how much a material stretches for the
force applied
The initial linear region is the straight diagonal line showing a linear
correlation between force and extension meaning they increase at the
same rate- Hooke’s Law
At some point the graph will begin to curve as this is when the object
reaches it elastic potential.
,1.24
Elastic behaviour is the way that when you stretch an object with this behaviour it will return to its original
shape after the forces stop stretching it. (e.g. when you let an elastic band go it goes back to its round shape).
If you stretch it beyond its elastic limit the object will not return to its original shape. A moment of silence
for our deformed object. Forever in our hearts
1.25
Momentum = mass x velocity
p=mxv
Momentum is measured kilogram metres per second (kg m/s
1.26
If the time taken for momentum to change is increased the overall force felt is decreased.
Air bags in cars increase the time it takes for the cars momentum to reach zero, meaning the
passengers feel less of the force- increasing the time until momentum of a body reaches zero reduces
the force felt.
Seat belts prevent the person from hitting the seat in front/dashboard. It stretches and slows the
person down, allowing them to stay within the main body. When the impact reaches the main body,
the person goes forward, and the seatbelt stretches to increase collision time.
The crumple zone increases the time to decelerate of the car. The front and back of the car crumple
in such a way that the force takes a longer time to reach the main body of the car
1.27
The total momentum of a system stays the same with no external
forces acting, such as friction
Momentum before collision = momentum after collision
Before impact:
m1u1 + m2u2 (mass of red x initial speed of red + mass of blue x initial speed of blue) = total momentum
before
m1v1 + m2v2 (mass of red x final speed of red + mass of blue x final speed of blue) = total momentum after
Using these two equations, the velocity of one of the objects after the collision can be found if the other
three velocities and both masses are known
Remember if one object going left and one going right, one of the velocities is positive and one is
negative
1.28
Force = change in momentum / time taken
F = (mv – mu) / t
Electricity
2.7
Parallel circuits are used for domestic lighting
Positives Negatives
Parallel The components can be individually controlled with their
own switches
If one component stops working the other can continue to
function
Series All of the components can be controlled by a single switch Components cannot be controlled
separately
If one component stops working
they all do
2.8
, The amount of current passing around a series circuit depends on:
The voltage of the power source
The number and type of components in the circuit (which affects its total resistance)
Increased voltage = increased current (for a series circuit)
Increased number of components (for a given voltage) will decrease the current in a series circuit
2.9
As the voltage across a component is increased, the current in the component also
increases
Diode: only allows current to pass in one direction; if voltage is applied in opposite
direction the diode has a very high resistance
The diagram shows how to test how current varies with voltage in different components
(.g. wire, bulb, resistor, diode)
IV graphs:
Resistance = I / V = gradient
Waves
3.2
Rarefaction
Longitudinal waves = waves where the vibrations are parallel to the direction of travel of the wave
(spread out)
Compression (close together)
Wavelength
Transverse waves = waves in which oscillations (vibrations) are perpendicular to the direction of
energy/information transfer
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