# Homework Help: Rotation Velocity on a boomerang

1. Dec 1, 2016

### RicardoMarques

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

How do I calculate the rotation velocity of a boomerang assuming that the period is like 0.5 seconds ? Considering a boomerang made of 3 rectangles, with an angle
of 120 degrees between two of those rectangles... According to internet..we must consider a velocity of throwing and a velocity of rotation and I don't know how to calculate this second one..
2. Relevant equations
3. The attempt at a solution

I was thinking of calculating angular velocity and then use V = w.R where R radius but I get values a little bit too high

2. Dec 1, 2016

### jbriggs444

What do you mean by "rotation velocity"? If you already know that it rotates with a period of 0.5 seconds then calculation of its rotation rate would seem to be rather simple.

Are you, perhaps, asking to calculate the rotation rate based on the linear velocity of the boomerang and an assumption that the end of the blade that is held in the hand is stationary at launch?

3. Dec 1, 2016

### RicardoMarques

Is exactly that my question

4. Dec 1, 2016

### jbriggs444

So we have the linear velocity of the boomerang as a given. Let's call that "v".

When we say that the boomerang is moving at v, it suggests that there is a point that is moving at v and that the boomerang is rotating around that moving point. That point has a name. Can you name it?

5. Dec 1, 2016

### RicardoMarques

I want to know this "a" assuming that the period is like 0.5... In the paper i read about it they call that velocity "a" rotation velocity... but is given i m/s and angular velocity is in rad/s, so im kinda confused about this

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6. Dec 1, 2016

### jbriggs444

I would have called it a "tangential velocity". It will be given by the rotation rate (in rad/s) multiplied by the radius.

If the radius is measured in meters, the resulting tangential velocity will be in meters/sec