Question

A horse runs on a circular track of length 720 metres in 20 seconds and returns to the starting point. Calculate the average speed.
A. $36 metres/second$
B. $0 metres/second$
C. $18 metres/second$
D. $72 metres/second$

Answer 1

Average speed of a body is calculated by dividing the total distance travelled with total time taken to cover the distance. In the question we are given with both the distance and the time. Substitute the values in the formula to calculate speed and find the value of the speed.

Complete step by step answer:
We are given that a horse runs on a circular track of length 720 metres in 20 seconds and returns to the starting point.
We have to calculate the average speed with which the horse ran.
Speed is the ratio of total distance travelled and total time taken to travel that distance.
$Speed = \dfrac{{distance}}{{time}}$
Given the total distance travelled by the horse on a circular track is 720 metres.
Total time taken is 20 seconds.
$Speed = \dfrac{d}{t} \\\ d = 720m,t = 20\sec \\\ Speed = \dfrac{{720}}{{20}} \\\ Speed = 36m/\sec \\\$
Therefore, the average speed of the horse when it travels a length of 720m in 20sec is 36metres/ second.
From among the given options, Option A is correct, which is $36metres/second$

Note: Speed is the ratio of total distance and total time taken to travel this distance whereas velocity is the ratio of total displacement and total time taken to travel this displacement. Speed and Velocity are not the same. Speed is a scalar quantity whereas velocity is a vector quantity. So do not confuse seed with velocity. The units of Speed are metres/ second or kilometers/ hour.