Question

the wheels of car of a diameter 80cm each.how many complete revolution does each wheel make in 10 minutes when the car is travelling at the speed of 66km per hour?

Answer 1

Diameter of the wheel (d) = 80 cm
Time(t)=10 minutes
speed (s)= 66 km/h
now Radius of the wheel (r)=d/2 = 80/2= 40 cm
Distance covered in 1 revolution = Circumference of the wheel
= 2. pi.r
=2×(22/7)×40
=(44×40)/ 7
=1760/7
Now Speed =distance/time
=>distance= speed*time             (minute converted to hour ie 1min=1 hr/ 60)
=66 *(10/60)
=11km
=11*1000m
=11*1000*100 cm
=1100000
Number of revolution= total distance / distance covered in 1 revolution
=1100000/(1760/7)
=7700000/1760
=4375 
 
Hope this Helps you.
  

Answer 2

Answer:

Step-by-step explanation:

Given :-

Diameter of the wheel of the car = 80 cm.

Radius, r = 80/2 = 40 cm.

Time taken by wheel, t = 10 minutes.

Speed of a car, S = 66 km/h.

To Find :-

Revolution by car.

Solution :-

Let the number of revolution by the wheel be x.

According to the Question

Circumference of wheel  = 2πr

= 2π (40)

= 80π cm

Speed of car = 66 km/h

= (66 × 100000/60) cm/min

= 110000 cm/min

Time taken by wheel = 10 minutes

= 110000 × 10

= 1100000 cm

Distance travelled in 1 revolution (circumference) = Distance travelled in 10 minutes

⇒ x × 80π = 1100000

⇒ x = 1100000 × 7/80 × 22

⇒ x = 35000/8

⇒ x = 4375

Hence, each wheel of the car will make 4375 revolutions.