Question

The radius of the wheel of a vehicle is 35m. The wheel makes 10 revolutions in 6 seconds. The speed of the vehicle is :

• A. 70 km/hr
• B. 13.2 km/hr
• C. 17.5 km/hr
• D. 20 km/hr

Answer 1

The Correct Option is B

To find the speed of the vehicle, we need to first determine the distance covered by the wheel in one revolution and then use this to find the total distance covered in a given time. Finally, we will convert this distance into speed.

1. Calculate the circumference of the wheel: The circumference \( C \) of a circle is given by the formula:

\( C = 2 \pi r \)

where \( r \) is the radius of the wheel. Here, \( r = 35 \) m, so:

\( C = 2 \times \pi \times 35 \approx 220 \) m

2. Find the distance covered in 10 revolutions: The total distance \( D \) is given by:

\( D = 10 \times C = 10 \times 220 = 2200 \) m

3. Calculate the speed in meters per second: The wheel covers this distance in 6 seconds. So, the speed \( v \) in m/s is:

\( v = \frac{2200}{6} \approx 366.67 \) m/s

4. Convert m/s to km/hr: To convert meters per second to kilometers per hour, multiply by 3.6:

\( v_{km/hr} = 366.67 \times 3.6 \approx 13.2 \) km/hr

Therefore, the speed of the vehicle is 13.2 km/hr.