Ok The May/June cambridge exam is comming fast and so you like to study out the following before appearing !

1.     Units of measurements

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SI units (Systeme International d’ Units)

1.  Length – Meter (m)
2.  Mass – Kilogram (kg)

• The greater the mass of an object, the greater is its resistance to any change in    motion.
• The greater the mass of an object, the greater is the earth’s gravitational pull   upon it.
3. Time – Seconds (s)
4. Volume – Meter Cubed (cm3)
• NOTE – a. Volume of a rectangular = Length x Width x Height
5. Volume of a cylinder = pr2 x Height

2. Speed, Velocity and Acceleration

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Speed and velocity

Unit of speed = Meters per second (m/s)

·       
 If an object moves between two points in a measured time its average speed =      Distance moved ÷ time taken

·          VELOCITY indicates the speed at which an object travels at a particular direction.                                                                                                                                     Average velocity = distance moved in a particular direction ÷ time taken.

·        Quantities such as velocity that have both magnitude and direction are known as vector quantities.

·          If the velocity of an object is constant or UNIFORM the speed and the direction is the same

Acceleration

Acceleration is a vector quantity. An object accelerates whenever the velocity changes.

AVERAGE VELOCITY = GAIN IN VELOCITY ÷TIME TAKEN

Unit of acceleration = m/s²

1.      Distance- time graphs

Ina d.istance- time graph, the line of the graph becomes steeper as the distance travelled every second increases.

·         The gradient of distance-time graph is numerically equal to the velocity.

2.      Velocity-time graphs

·         The area under a Velocity-time graph is numerically equal to the distance.

·         The gradient under a Velocity-time graph is numerically equal to the acceleration.

Equations of Motion

1.     V = u+at

2.     S = ½(v+u)t

3.     S = ut + ½ at²

4.     V² = u² +2as