Question

Question — The radius of a wheel of a cycle is 70 cm and it takes 5 min to take 300 rotation. Find the speed of the cycle in km per hr

Answer 1

Answer:-

$\red{\bigstar}$The speed of the cycle is

$\large\leadsto\boxed{\sf\purple{15.84 \: km/hr.}}$

• Given:-

Radius of the wheel = 70 cm

5 minutes to take 300 rotations

• To Find:-

Speed of the cycle in km/hr. = ?

• Solution:-

Radius is 70 cm

Distance covered in one rotation = 2πr

→ $\sf{2 \times \dfrac{22}{7} \times 70}$

→ $\sf{2 \times 22 \times 10}$

→ $\bf{440 \: cm}$

Hence,

Distance covered in 300 rotations = 300 × 440 cm

→ 132000 cm

→ 1.32 km

• Distance of 1.32 km is covered in 5 min. i.e in 5/60 hrs.

Finding Speed,

$\pink{\bigstar}$$\large\boxed{\sf\red{Speed = \dfrac{Distance}{Time}}}$

→ S = $\sf{\dfrac{1.32}{5} \times {60}}$

→ S = $\sf{1.32 \times 12}$

→ $\large\sf\pink{S = 15.84 km/hr.}$

Therefore, the speed of the cycle is 15.84 km/hr.

Answer 2

$\large\bf\red\bigstar\blue{Given➠}$

radius of a wheel= 70cm or 70/100 m

time to take 300 rotation=5min or 300sec

___________________________

$\large\bf\red\bigstar\green{To\:Find➠}$

Speed of Cycle in km/h.

___________________________

$\large\bf\red\bigstar\purple{Solution➠}$

$circumference = 2\pi \: r$

=>2×22/7 ×70/100

=>44/10

area covered in one rotation➛4.4 m

area covered in 300 rotation➛44/10 ×300

➛1320 metre

time given➛300sec

then,

speed➽distance/time

➽1320/300. m/sec

IN KM/h➠

$\frac{1320}{300} \times \frac{18}{5}$

$15.84 \: km/hr. \: \: \: \: \red \bigstar \: answer \red \bigstar$