Question

calculate the speed...

Answer 1

Hello,

Here's the answer :-

The wheel is a circle.

The diameter of wheel = 50 cm

=> 2 x radius = 50 cm

=> Radius = 50/2 cm = 25 cm

Circumference of circle = 2 x pi x radius = 50pi cm.

In one revolution, distance covered = 50pi cm

In 210 revolution, distance covered = 50pi x 210 = 10500pi cm = 32970 cm approx = 329.7 m

According to qn,

The wheel covers 210 revolution in 1 min.

=> The wheel covers 210 revolution in 60 s.


So, speed of cycle =

329.7 m / 60 s = 5.495 = 5.5 m/s approx.

Hope it helped

Answer 2

Question :

Vanshika is cycling such that the wheels of the cycle are making 210 revolutions per minute. If the diameter of wheel is 50 cm, calculate the speed per hour at which Vanshika is cycling.

Answer :

The wheels of the cycle are making 210 revolutions per minute.

So, let us find the distance travelled in a minute.

We are given the diameter of the wheel as 50 cm. Hence, the radius of the wheel is 25 cm.

Circumference of the wheel : 2πr.

⇒ 2*22/7*25

⇒ 50*22/7

⇒ 1,100/7

⇒ 157.14 cm

So, Distance travelled in a minute = 157.14*210 = 32,999.4 cm.

Now, The Distance travelled in one hour = 32,999.4*60 = 1,979,964 cm.

Converting the Distance in km : 1,979,964/100000

⇒ 19.79964 km

⇒ Approx 20 km

Now, Speed = Distance/Time

⇒ Speed = 20/1

⇒ Speed = 20 km/hr

Hence, The speed at which Vanshika is cycling is 20 km/hr.