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.
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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: ->->->->->->->->->->->-> scussion:
If the positive direction is the direction that the system moves when the 6kg descends,
Fnetside1 = m * a = 5kg * 9.8 m/s^2 = 49 N (negative direction)
Fnetside2 = m * a = 6 kg * 9.8 m/s^2 = 58.8 N (positive direction)
Since the two forces are opposing, Fnet = 58.8N - 49N = 9.8 N, and since
a = F/m = 9.8 (kg * m/s^2)/11 kg = 0.89 m/s^2, so it accelerates 0.89m/s^2 in the direction of the 6kg mass.
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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: ->->->->->->->->->->->-> scussion:
So since it would be moving in the negative direction,
v0 = -1.8 m/s
a = dv/dt = 0.89m/s^2 = (vf - - 1.8m/s^2)/1 sec, so
0.89m/s^2 = vf + 1.8 m/s^2
vf = -0.91m/s
So it would be travelling 0.91m/s in the negative direction, or the direction of the 3kg mass descending.
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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: ->->->->->->->->->->->-> scussion:
They are in opposite directions, and the system slows down, and eventually goes in the positive direction. So at 2 seconds, the system would almost be at rest, and at 3 seconds, the velocity would be positive again and then would increase.
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10-12 min
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&#This looks very good. Let me know if you have any questions. &#