Phy 121
Your 'cq_1_12.1' 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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Masses of 5 kg and 6 kg are suspended from opposite sides of a light frictionless pulley and are released.
• What will be the net force on the 2-mass system and what will be the magnitude and direction of its acceleration?
answer/question/discussion: ->->->->->->->->->->->-> :
We have to determine the force of each mass before we determine the net force. The side with the 5kg mass has 9.8m/s^2 Newtons acting on the object as our acceleration. This gives us a force of 49 Newtons.
When we take our 6kg and multiply it by our acceleration of 9.8m/s^2. This gives us a force of 58.8 Newtons.
When we solve for our netforce we get 58.8 Newtons + (-49 Newtons). This gives us a net force of 9.8 Newtons.
I am not quite sure what it means by magnitude here. Do I need to find the maximum acceleration?
I also think that the acceleration is moving in a positive direction because the force is positive.
You have to start by declaring the direction you wish to regard as positive.
The magnitude of a quantity is its absolute value. Depending on which direction you choose as positive, you could get a net force of either 9.8 N or -9.8 N. The magnitude of the net force is 9.8 Newtons in either cae.
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• If you give the system a push so that at the instant of release the 5 kg object is descending at 1.8 meters / second, what will be the speed and direction of motion of the 5 kg mass 1 second later?
answer/question/discussion: ->->->->->->->->->->->-> :
If the object is moving at 1.8 m/s then it’s speed after 1 second would be 1.8m/s^2.
Your units aren't quite right. Your statement works (and I believe says what you intend) if it is slightly modified:
If the object is accelerating at 1.8 m/s^2 then it’s speed after 1 second would be 1.8m/s.
If we release the object starting at an initial velocity of 0 from the release point and it moves down then it is moving in the negative direction.
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• During the first second, are the velocity and acceleration of the system in the same direction or in opposite directions, and does the system slow down or speed up?
answer/question/discussion: ->->->->->->->->->->->-> :
In that one second interval, I would say that I think the system is speeding up. If it starts at zero and then makes it way to 1.8 m/s so I think this is showing that it is speeding up. In this example our velocity would be negative and the acceleration would be positive.
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35 minutes
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Solution
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