Matlab Primer - Revision history

Carver: /* Questions */

2012-11-05T16:08:19Z

‎Questions

2012-11-05T01:48:49Z

‎Running the program and plotting results

2012-11-05T01:29:53Z

‎The whole program

2012-11-05T01:20:44Z

‎Questions

2012-11-05T01:20:29Z

‎Questions

2012-11-05T01:17:19Z

‎Pendulum on a movable support

2012-11-05T01:16:28Z

‎Questions

2012-11-05T01:16:13Z

‎Questions

2012-11-05T01:13:08Z

‎Questions

2012-11-05T01:11:47Z

← Older revision		Revision as of 16:08, 5 November 2012
Line 282:		Line 282:

	* Try InitialAngle=pi, InitialVelocity = 1. What is different about this trajectory?		* Try InitialAngle=pi, InitialVelocity = 1. What is different about this trajectory?
		+
		+	* Try InitialAngle=pi, InitialVelocity = -1. What is different about this trajectory?

	* What happens for small angles when (sin(theta0) = theta0)?		* What happens for small angles when (sin(theta0) = theta0)?

@@ Line 117: / Line 117: @@
   InitialAngle = 5*pi/6;
   InitialVelocity = 0;
-  len = 1
+  len = 1;
-  dt = 0.0001
+  dt = 0.0001;
   stopTime = 10;

@@ Line 107: / Line 107: @@
   end
-Copy and paste the above code into your MATLAB editor, then save as pend.m.
+Copy and paste the above code into your MATLAB editor (if your editor is not visible, type "edit" into the command window, and press return).  Once the you have copied the above function into the editor, save as pend.m.
 ====Running the program and plotting results====

@@ Line 299: / Line 299: @@
 * Try with b = 1.  What do you see?
-* Try with b = 0.1.  How does this differ
+* Try with b = 0.1.  How does this differ?
 * Try with b = -1.  (Negative friction).  What happens?

← Older revision		Revision as of 01:20, 5 November 2012
Line 298:		Line 298:

	* Try with b = 1. What do you see?		* Try with b = 1. What do you see?
		+
		+	* Try with b = 0.1. How does this differ

	* Try with b = -1. (Negative friction). What happens?		* Try with b = -1. (Negative friction). What happens?

@@ Line 14: / Line 14: @@
 See http://en.wikipedia.org/w/index.php?title=Lagrangian_mechanics&oldid=516894618 for a full derivation.
-Challenge: implement this model, after seeing how to implement a simpler one, below.
+Challenge (not required): implement this model, after seeing how to implement a simpler one, below.
 ===Pendulum on a fixed support===

← Older revision		Revision as of 01:16, 5 November 2012
Line 299:		Line 299:
	* Try with b = 1. What do you see?		* Try with b = 1. What do you see?

−	* Try with b = -1. (Negative friction). What happens.	+	* Try with b = -1. (Negative friction). What happens?

@@ Line 291: / Line 291: @@
 :<math>\ddot\theta + \frac{g}{\ell} \sin\theta + b \dot\theta = 0.\, </math>
-* Use "Save As" to create a new function, initially the same as pend.m. Call the new function damped_pend.m.  This function has one more input parameter b, so add that to the parameter list then modify the function to add friction.  You can use animate without any modification. Reanimate will require one sight modification.
+* Use "Save As" to create a new function, initially the same as pend.m. Call the new function damped_pend.m.  This function has one more input parameter b, so add that to the parameter list then modify the function to add friction.  You can use animate without any modification.
 * Try with b = 0.  This turns friction off. You should get same as without friction.

@@ Line 281: / Line 281: @@
 ====Questions====
-* We use a very small time step (the variable dt).  Smaller means more accurate, but also more expensive to compute.  What happens when we increase the time step?
+* Try InitialAngle=pi, InitialVelocity = 1.  What is different about this trajectory?
-* Return to a small time step and try (initial angle, ang=pi), (initial angular velocity, vel = 1).  What is different about this trajectory?
+* What happens for small angles  when (sin(theta0) = theta0)?
-* What happens for small angles  (sin(theta) = theta)?
+* We use a very small time step (input argument dt).  Smaller time steps mean more accurate integration, but also more expensive computations.  What happens when we increase the time step?