cq_1_121

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PHY 241

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.

** CQ_1_12.1_labelMessages **

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: ->->->->->->->->->->->-> scussion:

ffriction =0N

assign positive direction to heavy side

6kg-5kg=1kg of mass not counterbalanced so only this 1kg will cause a net force. This mass is also on the positive side so we know the force and acceleration will be positive.

F=ma = 1kg*9.8m/s^2=9.8N

This 9.8N is distributed over the entire mass of the system

F=ma

A=f/m=9.8N/11kg=0.891 m/s^2 in the positive or heavy side direction

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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:

as previously stated heavy side down is positive. In this case the v0=-1.8m/s

no friction to take into account means acceleration will remain the same a=0.891 m/s^2

`dt=1s

vf = -1.8m/s + 0.891 * 1

vf=-0.909 m/s

`ds = (-1.8 + -0.909) / 2 * 1s

`ds=-1.3545m The 5kg mass will have dropped this distance in 1 sec

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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:

acceleration is positive velocity negative. They are opposites. This causes the system to slow down.

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&#Good responses. Let me know if you have questions. &#