Question

The diameter of the driving wheel of a
bus is 140 cm. How many revolutions per minute must the wheel make in order to keep a speed of 66 km/h ?​

Answer 1

Answer:

• 250 revolutions.

Step-by-step explanation:

Given

• Diameter = 140 cm
• Speed = 66 Km/h

To find

• Number of revolutions per minute

Solution

Distance to be covered in 1 min:

• (66 × 1000) m / 60
• 1100 m

Radius of wheel:

• (140/2) cm
• 70 cm
• 0.70 m

Circumference of wheel:

• 2πr
• (2 × 22/7 × 0.70) m
• 4.4 m

Number of revolutions per minute:

• (1100/4.4)
• 250

Hence, the wheel must make 250 revolutions per minute.