1. IGCSE Physics Viraj Rijal http://apphysicsc.com 1

2. * Speed is a scalar quantity (has no direction) and refers to how fast something is covering a given distance in a particular interval of time Example:- D= 100km t= 2hrs S=100km/2hrs S=50km/hr SI unit for speed: m/s Other units: km/hr, mi/hr http://apphysicsc.com 2

3. Instantaneous speed:- The Speed at any given instance in time Uniform Speed:- When a body is travelling equal distances in equal intervals of time. http://apphysicsc.com 3

4. * Velocity is a vector quantity (has a specific direction of travel) and is referred to as the rate of a body changing its position. * Or otherwise, the distance covered by a body over a period of time in a specified direction. SI unit for Velocity: m/s Other units: mi/hr, km/hr Velocity is direction aware, and when calculated, the direction of travel has to be mentioned. Ex. 150m/s East Formula Velocity can also have a negative travel, showing that the body is moving in the opposite direction. http://apphysicsc.com 4

5. * Just like uniform speed, uniform velocity is when to bodies travel equal distances in equal intervals of time, but with a specified direction. http://apphysicsc.com 5

6. * Acceleration is a vector quantity, which is defined as the rate at which an object changes its velocity. * An object is accelerating or decelerating if it is changing its velocity. http://apphysicsc.com 6

7. * Constant acceleration or deceleration is defined by the change of velocity at a constant rate at any given time. http://apphysicsc.com 7

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