Dropping a closed loop into a magbetic field

AI Thread Summary
When a closed loop is dropped into a magnetic field, it experiences a change in magnetic flux, inducing a current that generates opposing forces according to Lenz's law. This results in a net force that is less than the gravitational force, leading to an acceleration of less than 10 m/s², contrary to the initial assumption that the forces would cancel out. The discussion emphasizes that the induced forces do not cancel each other completely, as they act in opposition to the motion of the loop. Understanding Lenz's law is crucial to grasping why the acceleration is reduced. The conclusion is that the closed loop will indeed accelerate at a rate less than 10 m/s² due to the opposing induced forces.
sgstudent
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Homework Statement


The closed loop is vertical and the magnetic field is a north and south pole such that the looped end faces the magnetic poles.


A multiple choice question answer stated that the closed loop will have a smaller acceleration than 10mls

^2 as it would experience an opposing force. But if I look at it closely, won't the 2 induced force cancel each other so it will accelerate at 10m/s^2?



Homework Equations


None


The Attempt at a Solution


My explanation goes like this: when it is dropped into the magnetic field, it experiences a change in magnetic flux linkage and thus there would be a current induced induced it. since there is a current flowing perpendicular to the magnetic field, by Fleming left hand rule there will be 2 forces acting on the closed loops at the two edges there are equal and opposite. Hence, this cancels out the force which allows the downwards acceleration to be still 10m/s^2.


Is there something wrong with my concept here? It seems correct to me though. I hope you guys can answer me as soon as possible cos tomorrow is my physics O level paper thanks for the help!
 
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sgstudent said:

Homework Statement


The closed loop is vertical and the magnetic field is a north and south pole such that the looped end faces the magnetic poles.


A multiple choice question answer stated that the closed loop will have a smaller acceleration than 10mls

^2 as it would experience an opposing force. But if I look at it closely, won't the 2 induced force cancel each other so it will accelerate at 10m/s^2?



Homework Equations


None


The Attempt at a Solution


My explanation goes like this: when it is dropped into the magnetic field, it experiences a change in magnetic flux linkage and thus there would be a current induced induced it. since there is a current flowing perpendicular to the magnetic field, by Fleming left hand rule there will be 2 forces acting on the closed loops at the two edges there are equal and opposite. Hence, this cancels out the force which allows the downwards acceleration to be still 10m/s^2.


Is there something wrong with my concept here? It seems correct to me though. I hope you guys can answer me as soon as possible cos tomorrow is my physics O level paper thanks for the help!

do you have the answer since it's a MCQ?

Lenz's law?
 
bsbs said:
do you have the answer since it's a MCQ?

Lenz's law?

The answer is that the acceleration is less than 10m/s^2. But since they cancel out so shouldn't it be 10m/s^2?
 
Read about lenz's law about opposing induced force. It satisfied the answer and in actual fact, they do not cancel out.
 
bsbs said:
Read about lenz's law about opposing induced force. It satisfied the answer and in actual fact, they do not cancel out.

Why won't they cancel out? Since the current is the same at both ends?
 
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