Question

The wheel of a bicycle is 70m is diameter. How far has it can travelled in 720 revolution of the wheel ? The wheels makes 2 revolution/second. Calculate the speed of cyclist in km/h​

Answer 1

Given :-

• The diameter of wheel = 70m
• The revolution of wheel = 720
• The wheel make revolution per sec = 2 Revolution

To Find :-

• The speed of cyclist in km/h = ?

Solution :-

To calculate the speed of cyclist , at first we have to find the circumference of wheel by applying formula. Then calculate distance with the help of given clue in the question then calculate it's speed in km/h.

Calculation for circumference :-

⇢ Diameter of wheel = 70m

⇢ Radius of wheel = 70/2 = 35m

⇢ Circumference of wheel = 2 × π × r

⇢ 2 × 22/7 × 35

⇢ 2 × 22 × 5

⇢ 44 × 5

⇢ 220m

Calculation for Distance covered :-

⇢ Distance = Circumference of wheel × revolution

⇢ 220 × 720

⇢ 158400m

Calculation for Time taken :-

⇢ Time = revolution/2 sec

⇢ Time = 720/2

⇢ Time = 360 sec

Calculation for speed :-

Distance = 158400 m. Time = 360 sec :-

⇢ Speed = Distance /Time

⇢ Speed = 158400/360

⇢ Speed = 440 m/s

Calculation for speed in km/h :-

⇢ Speed = S × 18/5

⇢ Speed = 440 × 18/5

⇢ speed = 88 × 18

⇢ speed = 1584 km/h

Answer 2

Given value in question are as below,

The wheel of a bicycle is 70m in diameter

$D=70m$.

The wheels make 2 revolutions/second.

Find:

How far has it can travel in 720 revolutions of the wheel?

And the speed of cyclist in km/h​,

Circumfrence $=2\pi r$

$\begin{array}{l}=2 \times 22 / 7 \times 35 \\=2 \times 22 \times 5 \\=44 \times 5 \\=220 \mathrm{~m}\end{array}$

The distance cover by wheel in 720 revolutions

$\begin{array}{l}=220 \times 720 \\=158400 \mathrm{~m}\end{array}$

Speed of the cyclist

$S=\frac{Distance}{Time}$

$\\\begin{aligned}\text { Speed } &=158400 / 360 \\\text { Speed } &=440 \mathrm{~m} / \mathrm{s}\end{aligned}$

speed in terms of Km/hr

$\begin{array}{l}\text { Speed }=\mathrm{S} \times 18 / 5 \\\text { Speed }=440 \times 18 / 5 \\\text { speed }=88 \times 18 \\\text { speed }=1584 \mathrm{~km} / \mathrm{h}\end{array}$

Therefore the distance covered by the wheel in 720 revolutions is 158400m and the speed of cyclist in km/hr is 1584km/hr.