Advertisements
Advertisements
Question
The wheels of a car are of diameter 80 cm each. How many complete revolutions does each wheel make in 10 minutes when the car is traveling at a speed of 66 km per hour? [Use Π = 22/7]
Solution
Diameter of the wheel of the car = 80 cm
Radius (r) of the wheel of the car = 40 cm
Circumference of wheel = 2πr
= 2π (40) = 80π cm
Speed of car = 66 km/hour
= (66x100000)/60 cm/min
= 110000 cm/min
Distance travelled by the car in 10 minutes
= 110000 × 10 = 1100000 cm
Let the number of revolutions of the wheel of the car be n.
n × Distance travelled in 1 revolution (i.e., circumference)
= Distance travelled in 10 minutes
n x 80Π = 1100000
`n = (1100000xx7)/(80xx22)`
= (35000)/8 = 4375
Therefore, each wheel of the car will make 4375 revolutions.
APPEARS IN
RELATED QUESTIONS
The length of minute hand of a clock is 14 cm. Find the area swept by the minute hand in one minute. (Use π = 22/7)
An elastic belt is placed round the rim of a pulley of radius 5 cm. One point on the belt is pulled directly away from the centre O of the pulley until it is at P, 10 cm from O. Find the length
of the belt that is in contact with the rim of the pulley. Also, find the shaded area.
The radii of two circles are 19 cm and 9 cm respectively. Find the radius of the circle which has circumference equal to the sum of the circumferences of the two circles.
The length of a chain used as the boundary of a semicircular park is 108 m. Find the area of the park.
The side of a square is 10 cm. Find the area of the circumscribed circle. [π = 3.14]
Find the area enclosed between two concentric circles, if their radii are 6 cm and 13 cm respectively.
The sum of the radii of two circles is 10.5 cm and the difference of their circumferences is 13. 2 cm. Find the radii of the two circles.
The diameter of two circles are 28 cm and 24 cm. Find the circumference of the circle having its area equal to sum of the areas of the two circles.
The circumference o a garden roller is 280cm. How many revolutions does it make in moving 490m?
Diameters of different circles are given below. Find their circumference (Take π = `22/7`)
d = 28 mm
