Phy 201
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.
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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: ->->->->->->->->->->->-> :
#$&* I am very confused about how to sketch this scenario. I don’t understand how two objects moving away in different angles are supposed encounter each other. Unless, maybe the two objects are moving towards the origin: one object moving towards the origin from 120 degrees, and another moving towards the origin from 270 degrees out.
Imagine you have a compass that points in the positive y direction, so that the positive x direction is to the east.
120 degrees from the x direction would be 30 degrees west of north. Imagine you are moving in this direction.
270 degrees from the x direction is directly south. So imagine moving in the direction 30 degrees west of north, with a force (maybe from the wind?) acting directly toward the south.
• Suppose you are facing in the direction of motion. Do you perceive the component of the force along the line of motion to be forward or backward? Is this component in the direction of motion or opposite to the direction of motion?
answer/question/discussion: ->->->->->->->->->->->-> :
#$&* If I am facing the direction of motion, I could only imagine that the component of force is moving forwards. It is in the direction of motion.
• Will the object speed up, slow down or maintain a constant speed?
answer/question/discussion: ->->->->->->->->->->->-> :
#$&* Maintain a constant speed, I imainge…
• If you are facing in the direction of motion, then the line perpendicular to the direction of motion will run to your right and to your left. Is the component of the force perpendicular to the line of motion directed to the right or to the left?
answer/question/discussion: ->->->->->->->->->->->-> :
#$&* If I sketched my graph correctly, it’s to the right.
• Will the object veer to the right, to the left or maintain straight-line motion?
answer/question/discussion: ->->->->->->->->->->->-> :
#$&* Maintain a straight-line motion
• Which is greater in magnitude, the component of the force along the line of motion or the component perpendicular to the line of motion?
answer/question/discussion: ->->->->->->->->->->->-> :
#$&* I think the component of the force alone the line of motion will have a greater magnitude, and I say this only because the sin and cos of 120 are greater than the sin and cos of 270.
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about 15 minutes
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&#Please compare your 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. &#