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.
Average speed of a car between points A and B is 20 m/s, between B and C is 15 m/s and between C and D is 10 m/s. What is the average speed between A and D, if the time taken in the mentioned sections is `20s, 10s and 5s,` respectively?
Options:
(a) 17.14 m/s
(b) 15m/s
(c) 10 m/s
(d) 45 m/s