3 m long hypothetical plank with no mass balances on a pivot. The pivot point is located exactly half way along the length of the plank. Then, from one end of the plank a 1 kg mass is suspended, and from the other end a 2 kg mass is suspended. How far and in which direction does the plank have to move along the pivot point to allow it to maintain its balance?
Remember it's asking in which direction the plank will move not the pivot.
There’s another question is asking in which direction the pivot will move.
To make balance:
(Mass x arm) on one side of pivot = (mass x arm) on another site of pivot
Fa x arm = Fb x arm
1 x left arm = 2 x right arm
Right arm = 1/2 left arm
If total length of plank is 3 m, right arm is half of left arm:
Right arm: 1 m
Left arm: 2 m
As the pivot was in the middle of the plank so each arm was 1.5 m, so plank has to move toward the 1 kg mass (left) to obtain balance.
Correct Answer: 0.5 towards the 1 kg mass.
There’s another question is asking in which direction the pivot will move.
To make balance:
(Mass x arm) on one side of pivot = (mass x arm) on another site of pivot
Fa x arm = Fb x arm
1 x left arm = 2 x right arm
Right arm = 1/2 left arm
If total length of plank is 3 m, right arm is half of left arm:
Right arm: 1 m
Left arm: 2 m
As the pivot was in the middle of the plank so each arm was 1.5 m, so plank has to move toward the 1 kg mass (left) to obtain balance.
Correct Answer: 0.5 towards the 1 kg mass.
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