# NTNUJAVA Virtual Physics LaboratoryEnjoy the fun of physics with simulations! Backup site http://enjoy.phy.ntnu.edu.tw/ntnujava/

## JDK1.0.2 simulations (1996-2001) => kinematics => Topic started by: Fu-Kwun Hwang on January 29, 2004, 03:16:16 pm

Title: Spring Force and SHM
Post by: Fu-Kwun Hwang on January 29, 2004, 03:16:16 pm
Spring Force and SHM

Let us cosider the force exerted on a mass by a spring attached to it.

This force take the form F = - k X

Where X measures the displacement of the mass from an equilibrium
position;

k is a constant characteristic of the particular spring known as spring constant.

This force law is known as Hooke's law.

This Java applet let you familar with this kind of relation and simple harmonic motionÂˇC

How to play:

There is a spring on the table, a string is connected to the spring
over a light frictionless pulley.

You can attach mass/blocks to the spring :

1. Move the mouse button with the blocks

2. The color of those blocks above the mouse pointer will turn black.

3. Click the mouse button to attach those black blocks to the spring.

4. The mass of those attached blocks will be shown near another spring (to
the right).

The spring will relax to its equilibrium position.

You can detach mass/blocks from the spring

1. Move the mouse button within the region of the attached blocks.

2. The color of those blocks below the mouse pointer will turn black.

3. Click the left mouse button to dettach those black blocks to the spring.

4. If you click the right mouse button and drag it up/down,

5. the force exerted on the spring will not balance the weight of the mass.

It will starts to oscillate in simple harmonic oscillation (SHM)

Press the mouse button to suspend the animation, click it again to resume.

Press Stop button to reset the spring back to equilibrium position.

Press Reset button to reset parameters to default values.

 X-axis Y-axis blue dots displacement Force red dots displacement Velocity

ExercisesÂˇG
1. Find out the spring-constant?

2. Green dot is the equilibrium position. How to determine the smpiltude of
the oscillation?

3. Measure the peroid of the oscillation. What is the relation between mass
and the period?

4. What else did you find out?

If a spring with a mass attached to it is slightly stretched or compressed
and then let loose,

Many elastic systems (building, flagpoles, airplane wings, etc) behave
in a very similar fashion.

Title: Re: Spring Force and SHM
Post by: Fu-Kwun Hwang on September 27, 2009, 10:12:57 pm
This is a EJS version of the above applet!

Title: Re: Spring Force and SHM
Post by: ahmedelshfie on June 24, 2010, 07:00:58 pm
Error in XML source code prof
EJS console appear message: found   : boolean
required: int
public int _method_for_shape2_enabledPosition () {   return _isPaused(); }
^
1 error
Compilation produced an error!
Thanks

Title: Re: Spring Force and SHM
Post by: Fu-Kwun Hwang on June 24, 2010, 08:52:56 pm
I do understand why you have such error. I can not re-produce the same error.
It is working fine with my EJS version 4.2

It should be
public boolean _method_for_shape2_enabledPosition () {   return _isPaused(); }
public int _method_for_shape2_enabledPosition () {   return _isPaused(); }

Please try to quit your EJS. re-run it and comiple the same file again.

Title: Re: Spring Force and SHM
Post by: ahmedelshfie on June 24, 2010, 11:10:38 pm
May prof problem because I'm use another version is EJS_4.3.0
So i will test by version 4.2.7 but i have ask :
I can setup two versions from EJS in my PC and work without probelms ?

Title: Re: Spring Force and SHM
Post by: ahmedelshfie on June 24, 2010, 11:19:31 pm
Thanks prof,,wrong was from me when i use version 4.2.7 simulation Work very well.
Now no have problems  :D

Title: Re: Spring Force and SHM
Post by: Richard789 on February 15, 2016, 01:17:10 pm
Ya good one..Liked it.