Question

The radius of the wheel of a vehicle is 70 cm. The wheel makes 10 revolutions in 5 seconds. The speed of the vehicle is

• A. 29.46 kmph
• B. 31.68 kmph
• C. 36.25 kmph
• D. 32.72 kmph

Answer 1

Answer:

B. 31.68 kmph

Solution:

Formula Used:

1. Circumference of circle = 2πr

2. Speed = Distance/time 

3. To convert speed from m/s to kmph multiply by 18/5

Calculation: 

Total Distance covered = 10 × Circumference of wheel

⇒ Total Distance covered $=10\times{2}\times{\frac{22}{7}}\times{\frac{70}{100}}=44m$

Using the above formula -

$Speed =\frac{44}{5}\times{\frac{18}{5}}=31.68kmph$

∴ The correct answer is 31.68 kmph