Question

if a cyclist takes 2 minutes to complete half revolution on a circular path of 120m radius. what is the average speed?

Answer 1

Answer : Average speed, s = 3.14 m/s

Explanation :

It is given that,

Radius of the circular path, r = 120 m

Time taken by cyclist to complete half revolution, t =  2 minutes = 120 s  

Distance travelled in half revolution, $d=\dfrac{2\pi r}{2}=\pi r$

Average speed,

$s=\dfrac{\pi r}{t}$

$s=\dfrac{3.14\times 120\ m}{120\ s}$

$s=3.14\ m/s$

Hence, the average speed of the cyclist in circular path is 3.14 m/s.

Answer 2

"Given: cyclist covers a circular path.

Distance covered by the cyclist = half of the circumference of the circle

$=\quad \frac { 1 }{ 2 } \quad \times \quad 2\pi r$

$=\quad \pi r\quad m$

Given:

Radius of the circle = 120m

Distance covered = 120π

Time taken = $2 minutes =\quad 2\quad \times \quad 60\quad =\quad 120\quad seconds$

We know that,

$Speed\quad =\quad \frac { Distance }{ Time\quad Taken }$

$=\quad \frac { 120\pi}{ 120 }$

$=\quad \pi$

$Speed\quad =\quad 3.17"$