# SHM in Earth and in Moon

1. Nov 11, 2008

### SciencePF

Suppose that, on Earth, a mass is suspended on a vertical string and is executing an harmonic motion with
Period: T
Amplitude: A
Angular frequency: $$\omega$$

Now all the system is put in the Moon. What changes that system will have?

Thanks for you help
1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

2. Nov 11, 2008

### jonwell

Recall that the period of simple harmonic motion is , and so depends on gravity (g). Since gmoon is smaller than gearth, the period will be greater.

3. Nov 12, 2008

### SciencePF

And what goes to happen with the amplitude of motion? Equal on Earth and Moon?

4. Nov 12, 2008

### jonwell

Yes, the amplitude in this case is arbitrary, it just equals A. In other words if you start a pendulum swinging on earth by pulling it to A, then go to the moon and start it again by pulling it to A, the difference is in the period (which gets longer by the relationship above).

If you do the same experiment but want to keep the period constant, then you'll need to swing a shorter amplitude on the moon.

5. Nov 12, 2008

### SciencePF

But, in this site, has a simulation, and things don't work as you said!
http://www.walter-fendt.de/ph14e/springpendulum.htm" [Broken]

Last edited by a moderator: May 3, 2017
6. Nov 12, 2008

### LowlyPion

I think that you mean this simulation:
http://www.walter-fendt.de/ph14e/pendulum.htm

The spring pendulum carries the spring constant wherever it goes.

Last edited by a moderator: May 3, 2017
7. Nov 12, 2008

### SciencePF

My initial question,
-----------------------------------
Suppose that, on Earth, a mass is suspended on a vertical string and is executing an harmonic motion with
Period: T
Amplitude: A
Angular frequency: $$\omega$$
Now all the system is put in the Moon. What changes that system will have?
--------------------------------------
http://www.walter-fendt.de/ph14e/springpendulum.htm" [Broken]

It seems no change will occur.

Sorry, for this post and thanks for your collaboration.

Last edited by a moderator: May 3, 2017