Question

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

Answer 1

Radius = 80 ÷ 2
= 40 cm

[ 1 km = 1000cm]
[ 1 m = 100 cm ]

Speed = 66 km / hour

= 66 × 1000 × 100 ÷ 60

= 110000 cm / minute

Time = 10 minutes

• Travelling of 1 complete revolution by wheel ;

= speed × time
= 110000 × 10
= 11,00,000 cm

Circumference of wheel = 2pie R

= 2 × 22 ÷ 7 × 40
= 1760 ÷ 7 cm

( 1760 ÷ 7 ) cm distance travelled = 1 revolution

1 cm distance travelled = 1 ÷ 1760 revolution

11, 00, 000 cm distance travelled ;

= 7 ÷ 1760 × 11,00,000
= 625 × 7

= 4375 ( Ans.)

# Hope this helps :-)