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JobHunter69
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I'm very confused on this problem. A pulley has two hanging blocks on either side with one having a greater mass. To find the torque, do I have to add the tensions of both the blocks or subtract the tensions, the positive being the hanging block that generates a counterclockwise spin? I thought I needed to subtract the tensions, but for some reason I'm only getting the right answer when I add the two tensions.

The question states to find the acceleration of block A which has a mass of 4.5 kg attached to a pulley with a radius of 0.14 meters, and 0.4 kg*m^2 for moment of inertia. Then there is another block B attached to the other end with mass 2 kg.

I keep getting the wrong answer when I solve this question by subtracting tensions to get torque, but keep getting the answer right when adding tensions to get torque???

Is it that the tensions which are written in terms of mass, gravity, and acceleration have acceleration that already signify which tension is positive and negative??

What I have for tension is T(a) - M(a)*g = -M(a)*a and T(b) - M(b)*g = M(b)*a

I'm very confused on this problem. A pulley has two hanging blocks on either side with one having a greater mass. To find the torque, do I have to add the tensions of both the blocks or subtract the tensions, the positive being the hanging block that generates a counterclockwise spin? I thought I needed to subtract the tensions, but for some reason I'm only getting the right answer when I add the two tensions.

The question states to find the acceleration of block A which has a mass of 4.5 kg attached to a pulley with a radius of 0.14 meters, and 0.4 kg*m^2 for moment of inertia. Then there is another block B attached to the other end with mass 2 kg.

I keep getting the wrong answer when I solve this question by subtracting tensions to get torque, but keep getting the answer right when adding tensions to get torque???

Is it that the tensions which are written in terms of mass, gravity, and acceleration have acceleration that already signify which tension is positive and negative??

I'm very confused on this problem. A pulley has two hanging blocks on either side with one having a greater mass. To find the torque, do I have to add the tensions of both the blocks or subtract the tensions, the positive being the hanging block that generates a counterclockwise spin? I thought I needed to subtract the tensions, but for some reason I'm only getting the right answer when I add the two tensions.

The question states to find the acceleration of block A which has a mass of 4.5 kg attached to a pulley with a radius of 0.14 meters, and 0.4 kg*m^2 for moment of inertia. Then there is another block B attached to the other end with mass 2 kg.

I keep getting the wrong answer when I solve this question by subtracting tensions to get torque, but keep getting the answer right when adding tensions to get torque???

Is it that the tensions which are written in terms of mass, gravity, and acceleration have acceleration that already signify which tension is positive and negative?

What I have for tension is T(a) - M(a)*g = -M(a)*a and T(b) - M(b)*g = M(b)*a

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Gert
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JobHunter69
JobHunter69
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When dealing with pulleys and hanging masses, does one add or subtract tensions to find torque?

I'm very confused on this problem. A pulley has two hanging blocks on either side with one having a greater mass. To find the torque, do I have to add the tensions of both the blocks or subtract the tensions, the positive being the hanging block that generates a counterclockwise spin? I thought I needed to subtract the tensions, but for some reason I'm only getting the right answer when I add the two tensions.

The question states to find the acceleration of block A which has a mass of 4.5 kg attached to a pulley with a radius of 0.14 meters, and 0.4 kg*m^2 for moment of inertia. Then there is another block B attached to the other end with mass 2 kg.

I keep getting the wrong answer when I solve this question by subtracting tensions to get torque, but keep getting the answer right when adding tensions to get torque???

Is it that the tensions which are written in terms of mass, gravity, and acceleration have acceleration that already signify which tension is positive and negative??