Velocity of a tire rolling down the road

[preluderacer]

Homework Statement

A tire is rolling along a road, without slipping, with a velocity v. A piece of tape is attached to the tire. When the tape is opposite the road (at the top of the tire), it's velocity with respect to the road is

The Attempt at a Solution

I have no idea where to even start with this. It has got me completely stumped

 

[Mindscrape]

$$v= \omega \times r$$ and if it is not slipping that is all the velocity.

 

[preluderacer]

so i cannot do this problem because the radius isn't given?

 

[willem2]

so i cannot do this problem because the radius isn't given?

The movement of a point on the outside of the tire is the superposition of a linear movement with a speed v, and circular movement. For a point that is touching the road, the velocities cancel.

 

[tiny-tim]

hi preluderacer!

so i cannot do this problem because the radius isn't given?

ah, but you know the speed of the centre of the wheel, and of the point of contact of the tyre on the ground,

sooo … ? ​

 

[preluderacer]

is it then 2v?

 

[tiny-tim]

yup!