Question

The diameter of a wheel of a car is 30cm. If the car travels at an average speed of 13.2m/s, find the number of revolutions made by the wheel per hour, giving your answer correct to the nearest whole number.

Answer 1

Approximately
`50420` revolutions (rounded to the nearest whole number.)

Explanation:

Convert the diameter of this wheel to meters:
`d = 30\; \rm cm = 0.30\; \rm m`.

Circumference of this wheel:

`\pi \, d = \pi * 0.30\; \rm m \approx 0.942\; \rm m`.

Distance travelled in one hour:

`\begin{aligned}v \cdot t &= 13.2 \; \rm m \cdot s^(-1) * 3600\; \rm s \\ &= 47520\; \rm m\end{aligned}`.

Number of revolutions required for covering that distance:

`\displaystyle (47520\; \rm m)/((\pi * 0.30\; \rm m)) \approx 50420`.