Question

The wheels of a car are of diameters 80cm ench. How many complete revolutions does
each wheel make in 10 minutes when the car is travelling at a speed of 66 km per hour.​

Answer 1

Step-by-step explanation:

distance covered by car in 10min = 110,000 x 10 = 11,00,000cm. distance covered in 10min / distance covered in one revolution. = 11,00,000/1 x 7/1760 = 4375 revolutions. Hence, in 10min each wheel of car makes 4375 revolutions.Oct 28, 2017

Answer 2

Answer:

• Number of revolutions = 4375

Given:

• Diameter = 80cm
• Distance = 66km
• Time = 10 minutes

To find :

• Number of revolutions

Solution:

Given:

• Diamter of circle = 80cm
• Radius = r = 80/2 = 40 cm

Now,

Distance coverd in one revolution = circumference wheel

As we know that circumference formula:

● 2 πr

● 2 × π × 40

● 80 π cm

Now we have to find distance covered :

As we know that,

speed = distance/Time

where,

• Distance is 66km (Given)
• Time = 10 minutes ( Given)

• speed = 66km / hr
• Time = 10 minutes = 10/60 hr = 1/6 hr

Putting the values:

⇢ 66 = distance / 1/6

⇢ 66 × 1/6 = distance

⇢ 11 = Distance

⇢ Distance = 11km

Distance is 11 km

Now,

⇢ Distance = 11 km

⇢ Distance = 11 × 1000 m

⇢ Distance = 11000m

⇢ Distance = 11000 × 100cm

⇢ Distance = 1100000 cm

Total distance = 1100000 cm

Now we have to find number of revolutions:

Number of revolutions = total distance / distance coverd in 0ne revolution

where,

• Total distance is 1100000
• Distance coverd in 1 revolution is 80 π

⇢ 1100000/80 π

⇢ 110000/8π

⇢ 1100000/80 × 22/7

⇢ 1100000×7/8×22

⇢ 4375

Hence, Number of revolutions is 4375