cq_1_193

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PHY 121

Your 'cq_1_19.3' report has been received. Scroll down through the document to see any comments I might have inserted, and my final comment at the end.

cq_1_193

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PHY 121

Your 'cq_1_19.3' report has been received. Scroll down through the document to see any

comments I might have inserted, and my final comment at the end.

** **

An object moving in the direction 120 degrees (as measured counterclockwise to the

positive x axis) encounters a net force whose direction is 270 degrees.

Sketch the force and its component along the line of motion, as well as its component

perpendicular to the line of motion.

answer/question/discussion: ->->->->->->->->->->->-> : ->->->->->->->->->->->-> :

I made an traditional x-y axis. Going into the 2nd quadrant, I sketched a ray at about

120 degrees. 270 degrees is straight down the y axis in the negative direction starting

at zero. But this isn't making sense. So I moved it over parallel, but now I don't think

it's 270 degrees.

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Your first picture was correct.

Suppose you are facing in the direction of motion. Do you perceive the component of the

force along the line of motion to be forward or backward? It this component in the

direction of motion or opposite to the direction of motion?

answer/question/discussion: ->->->->->->->->->->->-> : ->->->->->->->->->->->-> :

I would think that this would have something to do with velocity, however, just looking

at what I've drawn (which probably isn't correct) it seems to me that the 120 degree

trajectory will get knocked vertically when it by the 270 degree force.

&&&&

Facing 120 degrees would be forward and to the left. A force at 270 degrees would push back and to the left.&&&&

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If you are facing forward in the direction of the 120 degree vector, and a force pulls

on you in the direction of the 270 degree vector, that force must do one of the

following, as you perceive it:

The force must either

1. pull only in the direction opposite the one you are facing (i.e., backwards)

2. pull only in the direction you are facing (i.e., forward)

3. pull back and to the right

4. pull back and to the left

5. pull forward and to the right

6. pull forward and to the left

Which does it do?

Will the object speed up, slow down or maintain a constant speed?

answer/question/discussion: ->->->->->->->->->->->-> : ->->->->->->->->->->->-> :

&&&&I would expect the object to slow down because it's being pushed back and over.&&&&

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If you are facing in the direction of motion, then the line perpendicular to the

direction of motion will run to your right and to your left. Is the component of the

force perpendicular to the line of motion directed to the right or to the left?

answer/question/discussion: ->->->->->->->->->->->-> : ->->->->->->->->->->->-> :

&&&&It is going to the left&&&&

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Will the object veer to the right, to the left or maintain straight-line motion?

answer/question/discussion: ->->->->->->->->->->->-> : ->->->->->->->->->->->-> :

&&&&I would expect it to veer left&&&&

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Which is greater in magnitude, the component of the force along the line of motion or

the component perpendicular to the line of motion?

answer/question/discussion: ->->->->->->->->->->->-> : ->->->->->->->->->->->-> :

&&&&The component of the force along the line of motion. What force is perpendicular?&&&&

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*#&!

Your original picture sounds good.

I've inserted a question which, if you answer it, should get you oriented to the

situation.

&#Please see my notes and submit a copy of this document with revisions, comments and/or

questions, and mark your insertions with &&&& (please mark each insertion at the

beginning and at the end).

Be sure to include the entire document, including my notes.

20 min

Corrections inserted

self-critique #$&*

#$&* self-critique

self-critique rating

rating #$&*:

&#See any notes I might have inserted into your document, and before looking at the link below see if you can modify your solutions. If there are no notes, this does not mean that your solution is completely correct.
Then please compare your old and new solutions with the expanded discussion at the link
Solution

Self-critique your solutions, if this is necessary, according to the usual criteria. Insert any revisions, questions, etc. into a copy of this posted document. Mark any insertions with &&&& so they can be easily identified.
If your solution is completely consistent with the given solution, you need do nothing further with this problem. &#