phy201
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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Seed question 12
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: ->->->->->->->->->->->-> :
F= m * a
F= 5kg * 9.8m/s^2
f= 49 newtons
F= 6kg * 9.8 m/s^2
F= 58.8newtons
Fnet= 58.8 - 49 newtons
Fnet= 9.8 newtons
9.8 newtons = 11kg * a
a= .89 m/s^2
#$&*
If you give the system a push so that at the instant of release the 5 kg object is descending at 1.8 meters / second, what will be the
speed and direction of motion of the 5 kg mass 1 second later?
answer/question/discussion: ->->->->->->->->->->->-> :
VO=1.8m/s
a=9.8m/s^2
'dt= 1s
m= 5kg
Not bad, but you haven't declared a positive direction, and your signs are not consistent with the statement of the problem.
Vf= V0 + a * 'dt
Vf= 1.8m/s + 9.8m/s^2 * 1s
Vf= 11.6m/s
F=m * a
F= 5kg * 9.8m/s^2
F= 49newtons
a= f/m
a=49/5kg
a= 9.8m/s^2
#$&*
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: ->->->->->->->->->->->-> :
I think that the velocity and the speed are in the same directions, the systme is speeding up as it accelerates with gravity.
speed doesn't have a direction; speed is the magnitude of velocity
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about 30 minutes
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You weren't careful enough with positive and negative directions. I think you'll understand the solution as given, but if you don't be sure to ask. Otherwise no revision is requested.
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.