Plotting vector and two components with variable

[cliverlong]

Hi,

I can plot a vector in polar form, say [3,a], based at origin.

I can define its horizontal component as [3 cos (a), 0] and it appears as an arrow on the cartesian axes, based at origin. The component changes size as one would expect as the angle / argument of the first vector is changed.

I define a third vector based at the origin, the vertical component as [0, 3 sin(a)] and its definition appears in the status line below the axes. However, an arrow does not appear on the diagram to show the vector. I can define a "static" vector in polar form, [2, 90] say, and the arrow representing this vector does appear on the axes.

Regards

Clive

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Version 3.3.0002

[Support]

Hi Clive,

This appears to work for me but maybe I have misunderstood the problem. Please can you view the following video and check whether this is the same set of steps you have tried:

http://screencast.com/t/soNyzgiSPJk

Simon

[cliverlong]

(29-05-2012 07:33 AM)Support Wrote:  Hi Clive,

This appears to work for me but maybe I have misunderstood the problem. Please can you view the following video and check whether this is the same set of steps you have tried:

http://screencast.com/t/soNyzgiSPJk

Simon

Hello

Thanks for going to the trouble of reproducing my steps. Yes that is exactly what I did.

I have just tried it again - and it works !

Hmmm ...

Thanks for your time - this will be really useful when discussing and demonstrating resolving forces to perpendicular axes.

Clive

[Support]

Another way you might like to try this is by defining the initial vector from two points then create the component vectors geometrically and then the student can change the vector by dragging it rather than by using the constant controller. Just an alternative method for investigation.

1. Create two points, one at the origin.
2. Select the point at the origin, then holding shift select the other point.
3. Right-click and create vector.
4. Select the end point of the vector and create horizontal and vertical lines (from the right-click menu).
5. Repeat for the point at the origin (the lines will coincide with the axes).
6. In Point Mode hold down Ctrl and click on the intersections on the axes.
7. Create vectors to these intersections.
8. Hide all the gubbins.

http://screencast.com/t/m7FWtE5j

Simon

[cliverlong]

(30-05-2012 10:12 AM)Support Wrote:  Another way you might like to try this is by defining the initial vector from two points then create the component vectors geometrically and then the student can change the vector by dragging it rather than by using the constant controller. Just an alternative method for investigation.

<< SNIP REST >>

Simon

Nice. So there's both a "let's see what happens when we change the angle" approach and also a "let's see what happens when we move the end of the vector" approach.

Another display option, rather than hiding all the "construction" lines, is to convert the ones from the "free end" of the vector to dotted lines of say 1 point. Then the idea that the horizontal and vertical components are projections of the vectors on to the axes can be demonstrated.

Thanks

Clive

[Support]

Hi Clive,

Good idea, if you work this up into an activity it would be great to see it.

Best regards,

Simon

[cliverlong]

(31-05-2012 07:54 AM)Support Wrote:  Hi Clive,

Good idea, if you work this up into an activity it would be great to see it.

Best regards,

Simon

I think what I produce will be a little basic. To where should I load it? (dear liza)

Clive

[Support]

Hi Clive,

You can upload it here by adding it as a "New Attachment". Or send it to support AT autograph-maths.com.

Simon