- #1
mydir
- 2
- 0
Homework Statement
Hi I am really stuck on this question. It got handed out to us this morning and is due in Wednesday of this week. Any help would be great thanks.
A circular solid coil consisting of a circular disk of radius R = 20mm and mass M =
50 g pivoted through its diameter. It has 10 loop of thin wire round it circumference carry a current i = 400mA.
This coil is placed in a constant magnetic field of B = 100mT orientated such that the
torque on the coil is a minumum.
Show that if the coil is rotated by a small angle and released, it will undergo simple
harmonic motion about the minimum torque position. Calcualte the frequency of the
oscillation.
Homework Equations
Torque =μ(magnetic monent) ×B [Vector equation]
F(magnetic) = qv B
F(central) =(mv^2)/r
Torque= AIB sin(theta) [A is the area of the loop]
The Attempt at a Solution
I don't really know where to start. When it says the torque is a minimum does that its 0?
Should i solve the two force equations for r: r =mv/q B? Then solve for the frequency w=qB/m? Could the moment of inertia I = (1/4)mr^2, help me in this question? I mean I really don't know where to start and any help whatsoever would be much appreciated.
Thanks
mydir