Finding the Magnetic force on the coil

In summary, the conversation discusses a diagram that shows the relationship between Force and current I. The diagram includes a tangent length L to a circle, a force F pointing upwards at 90 degrees to vector B and perpendicular to vector L, and a small length dL. The speaker is considering resolving the force into X and Y components and integrating over a complete 2pi. They ask for advice on their approach and the direction of F in their drawing. The conversation also mentions the cancellation of horizontal components and the presence of N turns.
  • #1
Physicslearner500039
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6
Homework Statement
A voice coil in a loudspeaker has 50 turns of wire and a diameter of 1.56 cm, and the current in the coil is 0.950 A. Assume that the magnetic field at each point of the coil has a constant magnitude of 0.220 T and is directed at an angle of 60.0 Deg outward from the normal to the plane of the coil. Let the axis of the coil be in the y-direction. The current in the coil is in the direction shown (counterclockwise as viewed from a point above the coil on the y-axis). Calculate the magnitude and direction of the net magnetic force on the coil.
Relevant Equations
F=ILBSin(Θ)
1598025773773.png

Surely a tough one, I am doing it from the basics. This is the diagram i tried to draw showing the Force and current I
1598027435817.png


The Length L is the tangent to the circle. The Force F is pointing upwards at ##90 Deg## to the ##\vec B## and also perpendicular to ##\vec L##. I am considering a small length ##\vec dL = r d\theta##. Resolving the force into X and Y components and integrating over the complete ##2\pi##.

##Fx = \int_0^{2\pi} IRB\sin(30) d\theta ##
##Fy = \int_0^{2\pi} IRB\cos(30)d\theta ##

Is my approach correct or completely wrong? Please advise
 
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  • #2
Check the direction of F in your drawing. The current is going into the page at the point where you draw F.

If you consider the forces on diametrically opposite elements of current, what happens when you add their horizontal components?

Your integral for ##F_y## looks good except for maybe the overall sign. If ##\theta## varies from 0 to ##2 \pi##, how many times do you go around the cylinder?
 
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  • #3
TSny said:
Check the direction of F in your drawing. The current is going into the page at the point where you draw F.
I am not sure how i have done that mistake, the updated diagram is
1598076875045.png

The horizontal components cancel out. The vertical component is for N turns
##-\int_0^{2\pi} NIRB\cos(30)d\theta##
##-\pi NIRB\sqrt3 = -0.443 \hat j N##
 
  • #4
Looks right to me.
 
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1. What is the formula for finding the magnetic force on a coil?

The formula for finding the magnetic force on a coil is F = BIL, where F is the force in Newtons, B is the magnetic field strength in Tesla, I is the current in Amperes, and L is the length of the coil in meters.

2. How do you determine the direction of the magnetic force on a coil?

The direction of the magnetic force on a coil can be determined using the right-hand rule. Point your thumb in the direction of the current flow, and curl your fingers in the direction of the magnetic field. The direction in which your fingers point is the direction of the magnetic force.

3. Can the magnetic force on a coil be increased?

Yes, the magnetic force on a coil can be increased by increasing the current, increasing the magnetic field strength, or increasing the length of the coil.

4. What factors affect the strength of the magnetic force on a coil?

The strength of the magnetic force on a coil is affected by the current, magnetic field strength, length of the coil, and the angle between the current and the magnetic field.

5. How is the magnetic force on a coil used in practical applications?

The magnetic force on a coil is used in many practical applications, such as electric motors, generators, and magnetic levitation systems. It is also used in scientific research to study the behavior of charged particles in magnetic fields.

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