- #1
llhalsey
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Forces on a weight stack with the position of the pulleys so the weight is pulled up and the puller is moving a horizontally. Is it correct to use F=MG?
AI Thread Summary
The discussion centers on the forces acting on a weight stack when pulled horizontally, questioning the applicability of the formula F=MG. Participants agree that the force on the horizontal rope must support the weight, confirming the initial assumption. They note that when moving the weight vertically, the pulley system's mechanics must be considered for accurate calculations of work and power. The complexity arises from the need to account for the distance the rope is pulled, which is twice the distance the weight is lifted due to the pulley configuration. Overall, understanding the dynamics of the pulley system is crucial for precise calculations in this scenario.
- #2
berkeman
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llhalsey said:
Without a diagram it's hard to say for sure, but if I'm picturing it correctly, I think the answer is yes.
- #3
- #4
berkeman
Admin
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llhalsey said:
The force on the horizontal rope has to support the weight of the object, so your assumption is correct. However, if you start moving the weight up or down, the pulley system has to factor into any other calculations (work, etc.).
BTW, I've moved this thread to the Homework Help forums, where all schoolwork-type questions should be posted.
- #5
HallsofIvy
Science Advisor
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I note that there are two lines from the weight to the pulley. That means that you will have to pull the rope on the left twice the distance you lift the weight.
- #6
llhalsey
- 3
- 0
SO to calculate work = FD is it as simple as the distance the rope is pulled * mass of the wt *g. and Power would be divided by the time it takes to pull the distance or is there something specific with a pulley system that needs to be take into account?
I multiplied the values first without the error limit. Got 19.38. rounded it off to 2 significant figures since the given data has 2 significant figures. So = 19.
For error I used the above formula. It comes out about 1.48. Now my question is. Should I write the answer as 19±1.5 (rounding 1.48 to 2 significant figures) OR should I write it as 19±1. So in short, should the error have same number of significant figures as the mean value or should it have the same number of decimal places as...
Let's declare that for the cylinder,
mass = M = 10 kg
Radius = R = 4 m
For the wall and the floor,
Friction coeff = ##\mu## = 0.5
For the hanging mass,
mass = m = 11 kg
First, we divide the force according to their respective plane (x and y thing, correct me if I'm wrong) and according to which, cylinder or the hanging mass, they're working on.
Force on the hanging mass
$$mg - T = ma$$
Force(Cylinder) on y
$$N_f + f_w - Mg = 0$$
Force(Cylinder) on x
$$T + f_f - N_w = Ma$$
There's also...
This problem is two parts. The first is to determine what effects are being provided by each of the elements - 1) the window panes; 2) the asphalt surface. My answer to that is
The second part of the problem is exactly why you get this affect.
And one more spoiler:
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