Question

The wheel of a cart is making 20 revolutions per second. If the diameter of the wheel is 112 cm, find its speed in km/h,

Answer 1

To Find :

• we need to find it's speed in km/h

Given :

• Diameter of wheel = 112cm

› Distance covered in 1 revolution = Area of wheel = π × diameter

›› 22/7 × 112

›› 2464/7

›› 352 cm

So, Wheel covers 352 cm distance in 1 revolution.

As we know that,

› The wheel of a cart is making 20 revolutions per second.

So,

› Distance covered by wheel in 1 second

= 20 × 352

= 7040 cm/s

› Converting cm /s into km/h

• 1 km = 100000 cm
• 1 hour = 3600 Second

›› 7040 × 60 × 60

›› 7040 × 3600

›› 25344000 cm /hr

›› 25344000/100000

›› 25344/100

›› 253.44km/h

Hence,

• Speed of wheel is 253.44km/h .

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Answer 2

$\bf{\underline{QUESTION:-}}$

The wheel of a cart is making 20 revolutions per second. If the diameter of the wheel is 112 cm, find its speed in km/h,

$\bf{\underline{GIVEN:-}}$

• The wheel of a cart is making 20 revolutions per second.
• Diameter (d) of wheel is 112 cm

$\bf{\underline{SOLUTION:-}}$

• Distance covered in one revolution = π × d

→ 22/7 × 112

→ 352 cm

• Distance cover in 1 second = 20 × 352 = π × d

→ 20 × 352 = π × d

→ 7,040

Now,

• Distance cover in 1 sec = 60 × 60 × 7,040

→ 25,344,000

→ 25,344,000 ÷ 1000 × 100 km

→ 253,344 ,000 ÷ 100000 km

→ 253.344 km

$\bf{\underline{Hence:-}}$

• The speed of wheel = 253.344 km/h