Question

The wheel of a motorcycle is of radius 35 cm .How many Revolution per minute must the wheel make so as to keep a speed of 66 km per hour

Answer 1

Given

$\bold{Radius \ of \ the \ wheel} = 35 \ cm$

Circumference of the wheel = 2πr

                                               $= 2 * \dfrac{22}{7}*35$

                                               $= \underline{\underline{220 \ cm}}$

Speed of the wheel = 66 km/h

                                 $= \dfrac{66*1000}{60} m/min$

                                 $= 110000 cmmin^{-1}$

Therefore, no: of revolutions in one minute

= $\dfrac{110000}{220}$

= $\boxed{\boxed{\bold{500 \ revolutions}}}}$

                                                             

                             

Answer 2

✬ 5 Revolutions ✬

Step-by-step explanation:

Given:

• Radius of motorcycle wheel is 35 cm.
• Speed to be kept is 66 km/h

To Find:

• How many revolutions will the wheel take?

Solution: Circumference of motorcycle wheel is

★ Circumference = 2πr ★

$\small\implies{\sf }$ 2 x 22/7 x 35

$\small\implies{\sf }$ 2 x 22 x 5

$\small\implies{\sf }$ 220 cm

• Since speed is in Km/h units so we have to convert it into Cm/min •

• 1 km = 1000 m
• 66 km = 66 x 1000 = 66000 m /hr

• And 1 hour = 60 minutes therefore
• 66000 m/hr = 66000/60 = 1100 m/min

∴ Number of revolutions = 1100/220 = 5

Hence, Wheel have to keep 5 revolution per minute to keep speed of 66 km per hour.