Advertisements
Advertisements
प्रश्न
The wheel of the car makes 10 revolutions per second. If its diameter is 70 cm, find the speed of the car in km per hour.
उत्तर
Circumference = 2 π r = π d
`= 22/7 xx 70 = 220 "cm" = 2.2 "m"`
Circumference = 2.2 m
No. of revolutions = 10 per second
No. of revolutions per hour = 10 x 60 x 60 = 36000
Distance covered in one hour= 36000 x 2.2 = 79200 m /hour
Speed of the car in km/hour = `79200/1000 = 79.2` km / hour
Speed = 79. 2 km / hr
APPEARS IN
संबंधित प्रश्न
The radius of a circle is 7 cm. find the circumference of the circle.
In Figure , two concentric circles with centre O, have radii 21cm and 42 cm. If ∠ AOB = 60°, find the area of the shaded region. [use π=22/7]
In Fig. 9, is shown a sector OAP of a circle with centre O, containing ∠θ. AB is perpendicular to the radius OQ and meets OP produced at B. Prove that the perimeter of shaded region is
`r[tantheta+sectheta+(pitheta)/180-1]`
A bicycle whell makes 5000 revolutions in moving 11 km. Find the diameter of the wheel
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.
A gardener wants to fence a circular garden of diameter 21 m. Find the length of the rope he needs to purchase, if he makes 2 rounds of fence. Also find the costs of the rope, if it cost ₹ 4 per meter. (Take `pi = 22/7`)
The area of circle, inscribed in equilateral triangle is 154 cms2. Find the perimeter of
triangle.
An arc of length 15 cm subtends an angle of 45° at the centre of a circle. Find in terms of 𝜋, radius of the circle.
Four equal circles each of radius a, touch each other. Show that area between them is `6/7a^2`
The shape of the cross section of a canal is a trapezium. If the canal is 10 m wide at the top, 6 m wide at the bottom and the area of its cross section is `640m^2` , find the depth of the canal.
The circumferences of two circles are in the ratio 2: 3. What is the ratio between their areas?
The perimeter of the quadrant of a circle is 25 cm. Find its area.
The difference between the circumference and radius of a circle is 37 cm. The area of the circle is
The circumference of a circle is equal to the sum of the circumference of two circles having diameters 36 cm and 20 cm. The radius of the new circle is
In a circle of radius 21 cm, an arc subtends an angle of 60° at the centre. The length of the arc is
The circumference of a garden roller is 280 cm. How many revolutions does it make in moving 490 meters?
The diameter of a wheel is 1.4m. How many revolutions does it make in moving a distance of 2.2 kms?
The circumference of a circular field is 308 m. Find is:
(i) Radius
(ii) Area.
The circumference of a circle is eigth time the circumference of the circle with a radius of 12 cm. Find its diameter.
Each side of a square is 44 cm. Find its perimeter. If this perimeter is equal to the circumference of a circle, find the radius of the circle.
