Question

A car is moving with the speed of $22$ decimeter per second. If its wheel performs $7$ revolutions per second, then the diameter of the wheel is _________.

• A. $0.3$m
• B. $0.2$m
• C. $1.5$m
• D. $0.1$m

Answer 1

The correct option is D $0.1$m

A car is moving with the speed of $22$ decimeter per second.

Let $r$ be the radius of the wheel.

Therefore, distance covered by the wheel in $1$ revolution$=2\pi r$ dm

Distance covered in $7$ revolution$=14\pi r$ dm

Speed $=\frac{14\pi r}{1}=\frac{22}{1}$

$=>14\times \frac{22}{7}\times r=22=>r=\frac{1}{2}dm$

Therefore, diameter $=1$dm $=0.1$m