Average Speed and Average Velocity-When an object is in motion, its position changes with time. So, the quantity that describes how fast is the position changing w.r.t. time and in what direction is given by average velocity.
It is defined as the change in position or displacement `(Deltax)` divided by the time interval `(Delta t)` in which that displacement occur. However, the quantity used to describe the rate of motion over the actual path, is average speed. It defined as the total distance travelled by the object divided by the total time taken.
A cyclist is moving on a circular track of radius 40 m completes half a revolution in 40 s. Its average velocity is
Options:
(a) zero
(b) `2 ms^(-1)`
(c) `4pi ms^(-1)`
(d) `8pi ms^(-1)`