QUESTION 6
Easy
If the diameter of a car tyre is 56 cm, then:
(i) How far does the car need to travel for the car to complete one revolution?
(ii) How many revolutions does the tyre make if the car travels 10 km?
SOLUTION
1
(i)
Diameter \(= 56\,cm\)
Radius, \(r = 28\,cm\)
Circumference \(= 2πr \,= 2 × \frac{22}{7} × 28\,= 176\,cm\)
The car needs to travel 176 cm to complete one revolution.
Radius, \(r = 28\,cm\)
Circumference \(= 2πr \,= 2 × \frac{22}{7} × 28\,= 176\,cm\)
The car needs to travel 176 cm to complete one revolution.
2
(ii)
Distance travelled \(= 10\,km\,= 10,00,000\,cm\)
Number of revolutions \(= \frac{Distance travelled}{Circumference}\,=\frac{1000000}{176}\,= 5681.818...\,≈ 5682\,revolutions\)
The tyre makes approximately 5682 revolutions.
Number of revolutions \(= \frac{Distance travelled}{Circumference}\,=\frac{1000000}{176}\,= 5681.818...\,≈ 5682\,revolutions\)
The tyre makes approximately 5682 revolutions.
🏆
Final Answer :
(i) 176 cm
(ii) ≈ 5682 revolutions
Concept Note
The distance travelled by a tyre in one complete revolution is equal to the circumference of the tyre.
Circumference \(= 2πr\)
Distance for one revolution = Circumference
Number of revolutions = Total distance ÷ Circumference