Question

A cyclist goes once a circular track of diameter 105 m in 5 mins. calculate his speed.

Answer 1

If a cyclist goes once round a circular track, the distance he covers is actually the circumference of the the circular path:

Circumference$\text{= 2πr}$

Given: Diameter$\left(d\right)\text{= 105 m}$
Radius$\left(R\right)=\frac{d}{2}=\frac{105}{2}=52.5m$

Circumference$\text{= 2×3.14×52.5}$
$\text{=329.7 ≈ 330 m}$
So,
Distance$\text{=330 m}$
Time$\text{=5 min=5×60=300 s}$

$Speed=\frac{Distance}{Time}$ $=\frac{330}{300}=1.1\frac{m}{s}$