Advertisements
Advertisements
प्रश्न
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.
उत्तर
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
संबंधित प्रश्न
The minute hand of a clock is 10cm long. Find the area of the face of the clock described by the minute hand between 9 A.M. and 9.35 A.M.
The sum of the radii of two circles is 140 cm and the difference of their circumferences in 88 cm. Find the diameters of the circles.
The area of a minor sector of a circle is 3.85 cm2 and the measure of its central angle is 36°. Find the radius of the circle.
Choose the correct alternative answer for the following question.
A boy is cycling in such a way that the wheels of his bicycle are making 140 revolutions per minute. If the diameter of a wheel is 60 cm, calculate the speed (in km/h) at which the boy is cycling.
The perimeter of a circular field is 242 m. The area of the field is
The area of the circle is given below; find the diameter.
176 sq cm
A lawn is in the shape of a semi-circle of diameter 42 m. The lawn is surrounded by a flower bed of width 7 m all around. Find the area of the flower bed in m2 .
The shaded portion of the figure, given alongside, shows two concentric circles. If the circumference of the two circles is 396 cm and 374 cm, find the area of the shaded portion.
The diameter of a wheel is 1.26 m. The distance traveled in 500 revolutions is ____________.
