Phy 231
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:
Net force would be the force exerted on the 11kg mass by gravity. It would therefore be: 11 kg * 9.8 m/s^2 = 107.8 Newtons
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:
Using our equations learned previously:
If travelling 1.8 m/s, we know that after 1 s it will have travelled 1.8 m.
vf^2 = v0^2 + 0.5 a 'dt, where a = F / m, gives us:
vf^2 = v0^2 + 0.5 a 'ds
vf^2 = (1.8 m/s)^2 + 0.5 * 9.8 m/S^2* 1.8 m
vf^2 = 3.24 m^2/s^2 + 8.82 m^2/s^2
vf^2 = 12.06 m^2/s^2
vf = sqrt(12.06m^2/s^2)= 3.47 m/s
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:
Yes, the velocity and the acceleration of the 5 kg unit are in the same direction - the system is accelerating at 9.8 m/s^2
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30 mins
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If nearly equal masses are hung from two sides of a pulley they don't accelerate at 9.8 m/s^2. For a full explanation see the link below:
&#At least part of your solution does not agree with the solution and comments given at the link below. You should view the solution at that link and self-critique as indicated there.
Solution
This link also expands on these topics and alerts you to many of the common errors made by students in the first part of this course. &#