Phy 201
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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: ->->->->->->->->->->->-> :
Using F = m * a, and knowing that the a = 9.8 m/s^2, I determine the force of one side to be F = 5kg * 9.8 m/s^2 = 49 N and the other side being F = 6kg * 9.8m/s^2 = 58.8 N. If I subtract these two quantities, I get the net force to be 9.8 Newtons. This force will be in the negative direction on the same side of the pulley as the 6kg side.
• 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: ->->->->->->->->->->->-> :
I’m not too sure about the solution to this question, but I feel as though the 1.8m/s factors into the 5kg side’s force. In that case, the force on the 5kg side is F = 11.6m/s^2 * 5kg = 58 N. The other side’s force would remain as 58.8 N. If this be the case, the net force would be 0.8 N in the negative direction on the 6kg side. However, within that first second I am not really sure how to determine the speed the pulley will be moving in that time span….
• 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: ->->->->->->->->->->->-> :
The velocity and acceleration are in the same direction, since acceleration is acting down (in the negative direction) and the velocity comes about from pushing ‘down’ on that side. The system then slows down, before it begins to speed back up after the system reverses its direction.
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About 20 minutes...
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I didn't know how to determine the differences in speed and acceleration of the system with 2 different masses and when a velocity is applied in another direction.
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Solution
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