# A bicycle with tires 70 cm in diameter is traveling along a road at 25 km/hr. What is

1. Feb 21, 2012

### Daaniyaal

1. The problem statement, all variables and given/known data
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?

2. Relevant equations
A= 1/2r^2 ∅

3. 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.

Last edited: Feb 21, 2012
2. Feb 21, 2012

### 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!

3. Feb 25, 2012

### Daaniyaal

Re: A bicycle with tires 70 cm in diameter is traveling along a road at 25 km/hr. Wha

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