Question

A car wheel $60cm$ in diameter is turning at $8$ revolutions per second. When the car begins to slow uniformly to rest in a $14seconds$. Distance traveled by car in this time is

• A. (a)$211.2m$
• B. (b)$105.6m$
• C. (c)$52.8m$
• D. (d)$422.4m$

Answer 1

The correct option is A (a)$211.2m$

A car wheel $60cm$ in diameter is turning at 8 revolutions per second.

So distance covered in one second is equal to circumference of circle.

Circumference of circle =$\pi \times d$ where d is diameter of circle.

Cirumference =$\frac{22}{7}\times 60$

=$188.5714$cm

In one seconds it takes 8 revolutions so in 14 seconds it will take $14\times 8$ i.e $112$ revolutions

So distance covered in 14 seconds = number of revolution $\times$ distance covered in one second

= number of revolutions $\times$ circumference

=$112\times 188.5714$

=$21119.99$cm

=$211.2$m