Question

The wheel of a bicycle has a diameter of 70 cm and per makes 2 revolutions per second . Calculate to one decimal place the speed of the bicycle in km/h.

Answer 1

Correct Question :

A bicycle wheel, diameter 70 cm,is making 25 revolution in 10 sec.At what speed in km|/h is the bicycle traveling.

Solution :

We know that,

⟹ Circumference = 2πr

→ Circumference = 2* 22/7 * 35

→ Circumference = 44 * 5

→ Circumference = 220

∴ Distance travelled in one revolution = 220 cm

Distance travelled in 25 revolutions = 25 * 220 = 5500 cm

$\rule{200}{2}$

⟹ Speed = Distance/Time

→ Speed = 5500/10 * 100 m/s

→ Speed = 5.50 m/s

Now, In km/h

→ Speed = 5.50 * 36

→ Speed = 19.8 km/h