CHAPTER 1.4

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Possession - Chapter 1.1
> Length is measured in meters (m), Time is measured in seconds (s)
> mm - millimeter, milli-second (ms), km - kilometer (km), us - micro-second
> Always try to measure a larger quantity to reduce percentage error in measurement
> Stop-watch: 0.2s+0.2s = 0.4s reaction time error
> Ruler: 1/2 x (min division) for each end, if two ends, then error = min division
> speed = width of card / time measured for running trolley with erect card

Possession - Chapter 1.2
> Distance is a scalar, Displacement is a vector
> Vector has both magnitude (i.e. size) and direction
> Displacement is a vector that directs from the initial to the final position.
> Sometimes, you have to use Pythagoras theorem to find displacement.

Possession - Chapter 1.3
> Velocity is a vector, it has both magnitude and direction
> Velocity is the rate of change of displacement, unit is ms-1
> Acceleration is the rate of change of velocity, unit is ms-2
> 100 kmh-1 ~ 27ms-1
> Instantaneous speed / velocity is the speed / velocity at that particular time

Possession - Chapter 1.4
> Along a straight line, velocity is either positive or negative, which represents its direction.
> Usually, upward(rightward) is taken to be positive, downward(leftward) is taken to be negative.
> +5ms-1 and -5ms-1 have the same magnitude but opposite in direction.
> A higher acceleration means the velocity changes more per second.
> Acceleration is zero when speed is maximum. 
> Direction of motion = direction of velocity
> Direction of motion and direction of acceleration can be different!

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