Explain the following types of motion with one example for each:
$(i)$ Acceleration is positive
$(ii)$ Acceleration is negative
$(iii)$ Acceleration is zero.

(N/A) $(i)$ Positive acceleration: This occurs when the velocity of an object increases with time. Example: $A$ car accelerating from rest to gain speed on a straight road.
$(ii)$ Negative acceleration (Retardation/Deceleration): This occurs when the velocity of an object decreases with time. Example: Applying brakes to a moving car,causing it to slow down.
$(iii)$ Zero acceleration: This occurs when an object moves with a constant velocity (uniform motion),meaning there is no change in speed or direction. Example: $A$ car moving at a constant speed of $60 \ km/h$ on a straight,level road.