Question

Diameter of a 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 per hour?

Answer 1

To maintain a speed of 66 km/h, the bus wheel with a diameter of 140 cm must make approximately 248.7 revolutions per minute.

Step-by-step explanation:

The question relates to the topic of rotational motion in Physics, involving calculations to determine the revolutions per minute a bus wheel should make to maintain a certain speed.

Let's find the number of revolutions per minute required for the bus wheel with a diameter of 140 cm to maintain a speed of 66 km/h.

The circumference of the wheel is given by the formula C = πd, where d is the diameter of the wheel:

• C = π × 140 cm
• = π × 1.4 m

The speed in meters per minute is:

• 66 km/h = 66000 m/h
• = 1100 m/min (since there are 60 minutes in an hour)

The number of revolutions per minute (N) is the speed divided by the circumference:

• N = speed / circumference
• N = 1100 m/min / (π × 1.4 m)

Calculating this gives:

• N ≈ 248.7 rev/min
  

The wheel must make approximately 248.7 revolutions per minute to keep a speed of 66 km per hour.