# Homework Help: Mass of planet

1. Oct 29, 2015

### Dustin salinas

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

Stellar mass 3.8 x 10^30 kg
Star's orbital speed: 90 m/s
Planet's orbital speed: 95,000 m/s

Whats the mass of the planet in kilograms

2. Relevant equations

3. The attempt at a solution

2. Oct 29, 2015

### HallsofIvy

You seem to have forgotten to fill in "Relevant equations" and "The attempt at a solution"!

3. Oct 29, 2015

### Dustin salinas

This is my sons homework im just trying to get the answer and see if someone can show me how to get it so i can help him

4. Oct 29, 2015

### Andrew Mason

Can you find the distance to the centre of rotation from each body? What does that tell you about relative mass?

AM

5. Oct 29, 2015

### Dustin salinas

No thats all the information hes given

6. Oct 29, 2015

### Mister T

We don't give out answers to homework questions, so that's why you're being asked to find the center of rotation. It's the same point as the center of mass.

We could teach you how to make the right answer, but instead we teach you how to make sense of the physics involved in making the answer. If you communicate the former to your son and not the latter it won't have any instructional value.

7. Oct 29, 2015

### Dustin salinas

O ok apparently i came to the wrong forum. I thought i could just get help to teach him how to make the right answer. Like the formula to finding mass with those factors

8. Oct 29, 2015

### insightful

I suggest that your son join Physics Forums.

9. Oct 29, 2015

### Dustin salinas

Apparently him joining wouldnt get him closer to an answer

10. Oct 29, 2015