# Angular Speed of Venus

1. Sep 19, 2008

### Cate

Hi all, my homework question is this:

1. What is the angular speed in rad/s of a point on the equator of venus? (Rotation period: 243 days)

2. What is the angular speed in rad/s of a point on the surface of venus at latitude 11 degress south?

I know this isn't that difficult but I can't get the answer I thought maybe you use the formula

V= square root (GM/r) and then use the formula v= rw to solve for angular speed but then that doesn't take into account the 243 days.......

AS for the second question I have no idea

If anyone could point me into the right direction it would be appreciated...

2. Sep 19, 2008

### LowlyPion

Is the question about the orbital period around the sun?

Or the rotational period about its axis?

3. Sep 19, 2008

### Cate

o.k i solved 1. 2(pi)/ (20995200) # of seconds in 243 days.

I'm still stuck on ow to go about solving for 2.

4. Sep 19, 2008

### Cate

could someone please explain to me how to actor 11 degrees n question #2?

Thanks

5. Sep 19, 2008

### LowlyPion

What difference in angular rate will a point at 11 degrees rotate at?

6. Sep 19, 2008

### cepheid

Staff Emeritus
A particle at some point on the equator moves around in a great circle whose circumference is equal to the circumference of the planet (by definition). So you know how much *distance* the particle moves through, and you know how much *time* it takes to do so. Sooo.....

A particle at 11 degrees latitude moves around in a circle that is smaller than the equator. To figure out how to calculate this circle's radius, I would draw a diagram...there is some trigonometry involved.

7. Sep 19, 2008

### LowlyPion

While the Tangential speed will be affected by latitude, the angular velocity will not because the distance to the axis shrinks in direct proportion to its speed with increasing latitude. All points along a meridian travel at the same Angular speed. The answer is in radians/sec the same as for part 1.

8. Sep 19, 2008

### cepheid

Staff Emeritus
oh whoops...I didn't read the question properly. Didn't know we were looking for *angular* speed. Good catch.

9. Sep 19, 2008

### LowlyPion

No problem. Hated to have to give away the answer, but didn't want to confuse.

Cheers.