How Does Current Direction Affect Force in a Rectangular Loop?

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The discussion focuses on calculating the magnetic forces acting on a rectangular loop of wire carrying a current in a magnetic field. The loop has dimensions of 4 cm by 5 cm and carries a current of 2.8 A in a uniform magnetic field of 3.8 × 10^-4 T. The user has successfully calculated the torque for the x-axis and y-axis but is struggling to determine the forces Fa and Fb for the z-axis. The formula F=I*L*B sin(theta) is provided to find these forces, but the user is encountering difficulties with the calculations. Assistance is sought to verify the values being used in the formula to resolve the issue.
ahazen
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A rectanglular loop consists of 5 turns of wire carrying a current of 2.8 A. The loop is in the x-y plane, and the direction of flow of the current is shown in the figure. The loop has dimensions a = 4 cm and b = 5 cm. Consider a uniform magnetic field of strength 3.8 × 10-4 T in x, y, or z directions.

I need to find the:
-Fa on x-axis
-Fb on y-axis
-Fa on z-axis
-Fb on z-axis

For the X-axis, I found that torque is 1.064e-5 and Fb=0
For the y-axis, I found the torque is 1.064e-5 and Fa=0
I also found that the torque for z-axis is 0.

But, how do I find the other Fa and Fb?
I am given: F=I*L*B sin(theta)
 

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Hi ahazen,

ahazen said:
A rectanglular loop consists of 5 turns of wire carrying a current of 2.8 A. The loop is in the x-y plane, and the direction of flow of the current is shown in the figure. The loop has dimensions a = 4 cm and b = 5 cm. Consider a uniform magnetic field of strength 3.8 × 10-4 T in x, y, or z directions.

I need to find the:
-Fa on x-axis
-Fb on y-axis
-Fa on z-axis
-Fb on z-axis

For the X-axis, I found that torque is 1.064e-5 and Fb=0
For the y-axis, I found the torque is 1.064e-5 and Fa=0
I also found that the torque for z-axis is 0.

But, how do I find the other Fa and Fb?
I am given: F=I*L*B sin(theta)

By Fa, I assume you mean the magnitude of the magnetic force on side a due to the magnetic field, right? If so, then you have the formula; if you plug in your values (all you have to determine here is what theta is) what do you get?
 
yes, that's correct:) I'm still trying to work on the problem. Something is not working right when I plug the values in.
 
ahazen said:
yes, that's correct:) I'm still trying to work on the problem. Something is not working right when I plug the values in.

You seem to have the right formula; if you post the values you are plugging in and the result you get, I or someone else can try to verify it.
 
The book claims the answer is that all the magnitudes are the same because "the gravitational force on the penguin is the same". I'm having trouble understanding this. I thought the buoyant force was equal to the weight of the fluid displaced. Weight depends on mass which depends on density. Therefore, due to the differing densities the buoyant force will be different in each case? Is this incorrect?

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