Calculate Angular Velocity of 70cm Bicycle at 25km/hr

[Daaniyaal]

Homework Statement

A bicycle with tires 70 cm in diameter is traveling along a road at 25 km/hr. What is the angular velocity in radians per second?
(the answer given in the textbook is 19.8 radians per second)

Homework Equations

A= 1/2r^2 ∅
l = (radius)(central angle)

The Attempt at a Solution

Nvm I figured it out,

You first convert 25 km/h into cm/sec

25,000,00/60/60 = 694.5
Then, we go 2pi * 35 which gives us 219.8
We then divide 694/219.8

Which gives us 3.16

We multiply 3.16 with 2pi

And get 19.8 radians per second.

 

[tiny-tim]

Hi Daaniyaal!

That's correct, but why did you divide by π and then multiply by it again later?

Using the standard formula v = rω is much easier! ​

 

[Daaniyaal]

Hi Daaniyaal!

That's correct, but why did you divide by π and then multiply by it again later?

Using the standard formula v = rω is much easier! ​

Oh! Thanks! I didn't know the formula when I was doing this question, so I had to think it out.