Help on a physic 30 question

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In summary, the question asks to show that the units of 2\pi m/qB are equivalent to seconds. The student is unsure of how to get the unit for time from the given expression and asks for help. They attempt to use Fc = Fm but do not understand how 2\pi is used. A suggestion is made to use the Lorentz force law to relate the units to something more familiar.
  • #1

Homework Statement

Hello, i am in physics 30 and my teacher gave our class a worksheet for homework and I am stuck on the last question. Could anyone help me out please? Thanks.

Here is the question: Show that the units of 2[tex]\pi[/tex]m/ qB are equivalent to seconds.

How can I get the unit for time (s) from that? what do I have to show?

Homework Equations

The Attempt at a Solution

I tried using Fc = Fm but I don't get how 2[tex]\pi[/tex] is used in the equation? Or does it even have an effect and is there just as a constant with no units.
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  • #2
Welcome dulask :smile: Start by writing out all of the units for each symbol in the expression
[tex]\frac{2\pi m}{qB}[/tex]

I do not know what any of them are just by looking at them. I could venture a guess, but I rather not :wink:
  • #3
This problem is kinda annoying as B is in Tesla, q is a charge, m is a mass right? Well here's a nice little trick:

Do you know the Lorentz force law? F = q(E + v x B)? On one side is a force, something with units you should know and are far more comfortable with. On the other side, it has these crazy coulomb and tesla units! I'll assume you may not have gone over it but basically, dimensionally F = qvB! From there you should be able to figure it out.

What is Physics 30?

Physics 30 is a high school level course that covers advanced topics in physics, such as electricity and magnetism, optics, and modern physics.

Why do I need help on a Physics 30 question?

Physics 30 can be a challenging subject for many students, and it is normal to seek help when encountering difficult questions. Getting help can improve understanding and increase success in the course.

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There are many resources available for students seeking help with Physics 30 questions. You can reach out to your teacher, attend extra help sessions, join study groups, or use online resources such as videos, tutorials, and practice problems.

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Some common mistakes to avoid when solving a Physics 30 question include using incorrect formulas, not paying attention to units, and not showing all steps in the solution. It is also important to avoid making assumptions and to double-check calculations for errors.

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