A metal disk of radius 5.0 cm is mounted on a frictionless axle. Current can flo

Question

A metal disk of radius 5.0 cm is mounted on a frictionless axle. Current can flow through the axle out along the disk, to a sliding contact on the rim of the disk. A forte at thegone iGetween the station ary electrical c onta ct and the rotating the surrent i5 3.0 A, the disk rotätes with constant angular velocity. What's the frictiona 825 N This problem focuses on two concepts. One is the Faraday Law, the other is the conservation law of angular momentum. When the disk rotates at a uniform angular velocity, the net torque should be zero

Explanation / Answer

Force on a current carrying conductor is
dF = B*i*dr
So Torque on the differential element/ring will be,
dT = dF*r = Bi*rdr

Integrating from 0 to R,
T = Bi(R^2)/2

Now torque due to friction is,
T = fR

Equating the two,
f=BiR/2

={(1.75*0.05*3)/2}

=0.131 N

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

---