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Magnetic Fields

  • Thread starter brunie
  • Start date
  • #1
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A proton travels with a speed of 3.00 x 10^6 m/s at an angle of 44.0° with the direction of a magnetic field of 0.730 T in the +y direction.

(a) What are the magnitude of the magnetic force on the proton?
(b) What is its acceleration?

Ok for magnitude of force,

I used F = qvB sinø
= (1.6E-19)(3E6)(.73)sin44
= 2.437 E-13

But I was unable to find an equation for aceleration in a magnetic field in my notes, can anyone help me out?

Thanks
 

Answers and Replies

  • #2
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What does the path of the motion look like?
 
  • #3
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lol i have no idea,
but could this be solved just by using Fnet = ma
where Fnet incorporates the magentic force and gravitational force?
 
  • #4
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I doubt you need to include gravitational effects here.
The path of the motion is a hint as to how to find the solution. Any guesses?
 
  • #5
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well i kno initially its moving at the angle of 44˚, but the magnetic field should affect it to move in the positive y direction i think
 
  • #6
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Oh, you need to revisit the right hand rule to determine the direction of the force. This is an important effect for these types of problems.
 
  • #7
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but wouldnt using the RHR in this case introduce the 3rd dimension, because it would be coming out ?
 
  • #8
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???????????????????
 
  • #9
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yes, from the cross product.
 
  • #10
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so if we know it is coming out, how does it help solve for acceleration?
 
  • #11
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So at that point the force is out, does it remain in that direction?
 
  • #12
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i assume so
 
  • #13
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If the object has a net force acting on it, it will accelerate in that direction. So the velocity changes; remember that the direction of the force is dependent on the direction of the velocity vector, which changes.
 
  • #14
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so is there a way/formula to solve for acceleration by knowing this?
 
  • #15
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Sorry, if you are looking for me to give you a formula to plug numbers into, I cant help you.
If you understand the motion in your mind's eye, you will recognize the solution (hopefully).
 
  • #16
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fyi, i was right,
the equation has to do with fnet = ma
where fnet incorporates magnetic force

so next time if u dont kno wut ur talking about plz dont answer a question for sum1... instead of saying ok wut u said might make sense u overcomplicate everything
 
  • #17
340
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My apologies, I was for some reason thinking we were looking for the radius of motion.
My bad :smile:
In my opinion, I do not think that the questions I prompted were useless. I still think you should try to understand the motion of the charged object through the B field. :rolleyes:
 

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