Advertisements
Advertisements
Question
The wheel of a car makes 10 revolutions per second. If its diameter is 70cm, find the speed of the car in km per hr.
Advertisements
Solution
The Circumference of a Circle with diameter d is πd
The Circumference of a Circle with diameter 70cm is π x 70
= `(22)/(7) xx 70`
= 22 x 10
= 220cm
Total distance moved in 10 revolutions
= 2.2km
= 2200cm
distance moved in 1 second = 2200cm
⇒ distance moved in 1 hour
= 2200cm x 60 x 60
= 7920000cm
= `(7920000)/(100 xx 1000)`
= 79.2km
∴ Speed = 79.2km/hr.
APPEARS IN
RELATED QUESTIONS
In the given figure, O is the centre of the circle with AC = 24 cm, AB = 7 cm and ∠BOD = 90°. Find the area of the shaded region.
An arc of length 15 cm subtends an angle of 45° at the centre of a circle. Find in terms of ЁЭЬЛ, radius of the circle.
What is the perimeter of a square which circumscribes a circle of radius a cm?
Two circular pieces of equal radii and maximum area, touching each other are cut out from a rectangular cardboard of dimensions 14 cm тип 7 cm. Find the area of the remaining cardboard.
Find the area of a quadrant of a circle whose circumference is 88 cm.
Four equal circles are described about the four corners of a square so that each touches two of the others, as shown in the figure. Find the area of the shaded region, if each side of the square measures 14 cm.
The perimeter of the quadrant of a circle is 25 cm. Find its area.
The diameter of a circular field is 56 m. Find its circumference and cost of fencing it at the rate of тВ╣80 per m. (Take π =`22/7`)
The diameter of a cycle wheel is `4(5)/(11)"cm"`. How many revolutions will it make in moving 6.3km?
Ratio of the circumference of a circle to its diameter is denoted by symbol ______.
