Chapter 1
Quantities and units!
A PHYSICAL QUANTITY is a feature of something which can be measured.
I.E. LENGTH WEIGHT OR TIME OF FALL
LARGE and SMALL quantities are usually expressed in scientific notation
The elephant is large in comparison with the boy but small in comparison with the sky scraper.
The SI SYSTEM of UNITS!
 All quantities have a magnitude and a unit.
 The SI base units of mass, length, time electric current, thermodynamic temperature, and amount of substance are the Kilogram, metre, second, ampere, Kelvin and mole respectively.
 Units if all mechanical, electrical and thermal quantities may be derived in terms of these base units.
 Physical equations must be homogeneous. Each term in an equation must have the same base units.
Uncertainty
Uncertainty…
There are TWO different types of uncertainty, Systematic and Random. They can each be defined as the following:
Systematic uncertainty (or ‘error’) will result in all readings being too large or too small. This Uncertainty cannot be eliminated by taking an average of several values.
Examples include:
 Non zero reading on a meter
 Incorrectly calibrated scale
 Reaction time of experimenter
Random Uncertainty gives a rise to the scatter if readings about the true value. The uncertainty can be reduced by repeating readings and taking and average.
Examples include:
 Reading a scale
 Measuring out a certain volume of liquid
 Missreading a scale from the wrong position.
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A scalar quantity can simply be defined as a quantity that has magnitude,
As for a Vector, that is a Quantity that has both Magnitude and DIRECTION
EXAMPLES
 Mass: Scalar
 Speed: Scalar
 Weight: Vector
 Force: Vector
A VECTOR QUANTITY MAY BE REPRESENTED BY AN ARROW, WITH THE LENGTH OF THE ARROW DRAWN TO A SCALE TO THE GIVEN MAGNITUDE.
 Horizontal Component of a vector; FcosANGL
Vertical Component of a vector; FsinANGL
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Chapter 2
Kinematics
Ave. Speed= distance covered
Time Taken
Speed and Velocity are generally perceived to be the same thing, however in physics that are completely different.
The Difference between speed and velocity, is that a velocity is used to represent a vector quantity: the magnitude of how fast the particle is moving, and the direction at which it’s moving. Speed does not have a associated direction. Making them differ.
Ave. Velocity= displacement
Time Taken
FOUR EQUATIONS OF UNIFORM MOTION
 v= u + at
 s=ut +1/2 at^2
 v^2= u^2+2as
 Ave. V = (u+v)/2
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FREE FALL ACCELERATION:
All objects fall with the same uniform motion(g), its value is 9.8 m/s^2 and is directed downwards.
Eventually objects in free fall reach terminal velocity which is a maximum velocity.
PROJECTILE MOTION
Galileo first gave an accurate summary of this particular type of motion. He did so by splitting the motion in to its horizontal and vertical components.
Fx & Fy Each representing the vertical and horizontal components respectively.
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Chapter 3
Work Power Motion
ii WORK, POWER, & MOTION!!
 WORK; “I am going to work today”… WRONG
 WORK; “ I have finished my homework”…WRONG
 WORK; “Work is done when a force moves the point at which its at” … RIGHT
When a force of one Newton moves its point of application by one meter in the direction of the force, one joule of work is done
WORK DONE= pressure X change in volume.
THE ABILITY TO DO WORK IS CALLED ENERGY
Where m= mass , G= Gravitational pull, H= Height of object.
Where Mass times velocity squared is divided my 2.
HOOKE’S LAW
Provided the elastic limit is not exceeded, the extension of a body is proportional to the applied load.
F= K times the change in L.
K is the elastic constant.
ENERGY CAN NOT BE CREATED OR DESTROYED ONLY TRANSFERRED FROM ONE FORM TO ANOTHER….
Power is the rate of doing work.
Work done= power X time taken
Power= WORK DONE
TIME TAKEN
Power, like energy is a scalar quantity
Power= force X speed
TORQUE
The turning effect of a force is called torque
The torque is a force defined as the product of the force and the perpendicular distance of the line of action of the force from the pivot.
COUPLE
A couple consists of two forces equal in magnitude but opposite in direction
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Chapter 4
Force and Collisions

Every body continues in it’s state of rest, or of uniform motion in a strait line, unless compelled to change that state by a net force

For a body of constant mass, its acceleration is directly proportional to the net force applied to it.

Whenever a body exerts a force on another, the second exerts an equal and opposite force on the first.
Force= mass x acceleration (F=ma)
*The property of a body to stay in a state of rest or uniform motion is called inertia*
Weight=mass x the acceleration of free fall
Momentum = mass x velocity
P = mv
*the force acting on a body is equal to the rate of change of its momentum*
F =ma
*if no external force acts on a system, the total momentum of the system remains constant, or is conserved*
*if a constant force acts on a body for a time, the impulse of the force is given by the force x change in time*
COLLISIONS
Two kinds:

If the collision is elastic the kinetic energy before collision is equal to the kinetic energy after

Collisions in which total kinetic energy is not the same before and after the event are called inelastic
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Chapter 6
Charge = current x time
*the coulomb is that charge passing a point in a circuit when there is a current of one ampere for one second*
*the Resistance(R) of a wire is defined as the ratio of the potential difference across the wire to the current in it*
R= V/I or Potential Difference/ Current
Potential Difference = energy transferred (or work done)/charge
V= W/q
Energy Transferred = potential difference x charge
W= Vq
Potential Difference = power/ current
V= P/I
Electrical power= Current squared x resistance
Electrical Power P= VI= I^2R= V^2/R
OHM’S LAW
For a conductor at constant temperature, the current in the conductor is proportional to the potential difference across it.
*The resistively of a material is numerically equal to the resistance between opposite faces of a cube of the material, of unit length and unit crosssectioned area*
Kirchoff’s Laws

the sum of the currents entering a junction in a circuit is always equal to the sum of the currents leaving it.

The sum of the electromotive forces in a closed circuit is equal to the sum of the potential differences.
*the terminal potential difference is the p.d. between the terminal of a cell when a current is being delivered*
*A supply delivers maximum power to a load when the load resistance is equal to the internal resistance of the supply*
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