PHYSICS UNIT 2 NOTES

Here are my notes for Physics Unit 2 - if i need to make any corrections or I'm missing something - please tell me

But anyways, hope this will help

Good Luck!

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• Created by: Bessem
• Created on: 05-04-13 18:54
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Page 1

PHYSICS UNIT 2 NOTES

Physics

RESULTANT FORCES

Forces work in pairs
The Resultant force is simply what you get when you add forces together
But you can only add forces which are opposite each other
Find the resultant force by finding the difference, of the numbers if they are opposite…

Page 2

PHYSICS UNIT 2 NOTES

Mass = a measure of how much stuff you are made up of (kg)
Weight = mass x gravitational field strength W=mg (N) = kg x (N/kg)
Earth's gravity = 10
Space's gravity = 0 (WEIGHTLESS)
Moon's gravity = 1.67
The faster the object, the greater…

Page 3

PHYSICS UNIT 2 NOTES

KE increases with greater mass and greater speed

KE= ½ x mass x speed2

When the height is zero there is no GPE, the KE is at a maximum

MOMENTUM

Momentum is a useful quantity to consider when thinking about `unstoppability'
Momentum (kg/s) = mass (kg)…

Page 4

PHYSICS UNIT 2 NOTES

If you rub two insulating materials together, electrons will transfer from one to another
One will become positively charged (the one with that lost electrons), the other will
become negatively charged (the one that gained electrons)
If something is neutral (not charged e.g. water) then it…

Page 5

PHYSICS UNIT 2 NOTES

The size of an electric current (I) = The number of electrons flowing (Q) / through a
component per second (t)
I = Q/t
Where
o I = Current in Amps
o Q = Charge in Coulombs
o t = Time

Words Symbols Units
Current I…

Page 6

PHYSICS UNIT 2 NOTES

The current through a resistance at a constant temperature is directly proportional to
the proportional difference (voltage) across the resistor.
Ohmic conductor = it's resistance is constant
If the temperature is not kept constant it will not be directly proportional = not
following Ohm's law

IV…

Page 7

PHYSICS UNIT 2 NOTES

If you remove or disconnect one component, the circuit is broken and everything in the
circuit stops. (This is why most Christmas lights are now connected in parallel circuits,
because if one bulb goes out they all go out. The only advantage of Christmas lights
connected…

Page 8

PHYSICS UNIT 2 NOTES

An AC = the current flows in one direction then back in the direction where it came from
(it is constantly changing direction back and forth)
A DC = the current flows in the same direction
The UK Mains supply an ALTERNATING CURRENT
Cells & Batteries…

Page 9

PHYSICS UNIT 2 NOTES

1
F requency (Hz) = Time Period (s)

The time period is the time it takes to make a complete wave (from peak to peak)
To find the time period measure the horizontal distance between the two peaks using the
divisions (the squares on the x…

Page 10

PHYSICS UNIT 2 NOTES

FUSES

We want an appliance which will blow if the current is too much ­ reason for fuse
Fuse protects the appliance so we know when the appliance is getting damaged
If the fuse rating is too high for the appliance it is letting the appliance…