Question

Diameter of a wheel of a bus is 140 cm . How many revolutions per minute must a wheel take to move at a speed of 66km/hr​

Answer 1

Step-by-step explanation:

Thus, the wheel will make 250 revolutions per minute with the speed of 66km per hour.

Answer 2

Answer :

• 250 revolutions per minute must a wheel take to move at a speed of 66km/hr

Given :

• Diameter of a wheel of a bus is 140cm

To find :

• How many revolutions per minute must a wheel take to move at a speed of 66km/hr

Solution :

First we need to find the radius , To find the radius we will use the formula of radius

• Radius = D/2

Given, Diameter = 140cm

• Radius = D/2

• Radius = 140/2

• Radius = 70cm

Now, we will find the circumference of wheel :

As we know that,

• Circumference = 2πr

Where, r is radius

➞ Circumference = 2πr

➞ 2 × 22/7 × 70

➞ 2 × 22 × 10

➞ 440cm

Circumference = 440cm

Given that,

• Speed = 66km/hr

➞ Distance per hour = 66km/hr

➞ Distance per minute = 66 × 1000 × 100 / 60 cm

➞ Distance per minute = 11000cm

Finding the revolutions per minute :

We know that,

• Number of revolutions = Total distance per minute/revolutions (Circumference)

➞ Number of revolutions = 11000/440

➞ Number of revolutions = 1000/4

➞ Number of revolutions = 250

Hence, 250 revolutions per minute must a wheel take to move at a speed of 66km/hr