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given a square wire frame with a side of length L, placed in a constant extarnal magnetic field B, (B=B*[tex]\hat{k}[/tex]). a current of i flows through the frame anticlockwise(as shown by arrows in diagram)

the frame can turn freely about the x axis (which passes through its centre)

the frame has a linear mass density of λ

a) what is the force applied on the frame?

b) what is the momentum applied of the frame?

c) what is the angular acceleration of the frame?

------------------------------------------------

a) since the force applied would be ILxB,

the force on either side parallel to the field B has no contribution since ILB*sinθ=0 (θ=0/180)

for either side perpendicular to the field ILxB=ILB

therefore my total force on the frame would be 0+0+ILB-ILB=0

----------------------------------------------------

b) for the momentum i say that N=RxF=(L/2)*F=(L/2)*ILB=0.5L

and since i have 2 contributors to the momentum and the are both on x-,

N=-L

------------------------------------------------------

c) for the angular acceleration α, i need to somehow find the moment of enetria for a frame like this, and then i can say that N=

α=N/

can i use the moment of a pole 1/12(mL

given a square wire frame with a side of length L, placed in a constant extarnal magnetic field B, (B=B*[tex]\hat{k}[/tex]). a current of i flows through the frame anticlockwise(as shown by arrows in diagram)

the frame can turn freely about the x axis (which passes through its centre)

the frame has a linear mass density of λ

a) what is the force applied on the frame?

b) what is the momentum applied of the frame?

c) what is the angular acceleration of the frame?

------------------------------------------------

a) since the force applied would be ILxB,

the force on either side parallel to the field B has no contribution since ILB*sinθ=0 (θ=0/180)

for either side perpendicular to the field ILxB=ILB

therefore my total force on the frame would be 0+0+ILB-ILB=0

----------------------------------------------------

b) for the momentum i say that N=RxF=(L/2)*F=(L/2)*ILB=0.5L

^{2}IBand since i have 2 contributors to the momentum and the are both on x-,

N=-L

^{2}IB*[tex]\hat{i}[/tex]------------------------------------------------------

c) for the angular acceleration α, i need to somehow find the moment of enetria for a frame like this, and then i can say that N=

*I*αα=N/

*I*can i use the moment of a pole 1/12(mL

^{2}) and multiply it by 2 to take into account each side??? this doesnt seem right to me, what aout the other 2 sides wgich arent revolving about their centre???
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