Question

determine the magnitude of the required force
express your answer in terms of the variables ( b ), ( l ), ( v ), and ( r ).
( f_{\text{enemal}}=\frac{v b^{2} l^{2}}{r} )
part b
what external power is needed to move the rod?
express your answer in terms of the variables ( b ), ( l ), ( v ), and ( r ).

Explanation:

Step1: Recall the formula for power

Power \(P = Fv\), where \(F\) is the force and \(v\) is the velocity.

Step2: Substitute the force from part A

We know from part A that \(F_{external}=\frac{B^{2}L^{2}v}{R}\). Substitute this into the power formula: \(P = F_{external}v\).

Step3: Calculate the power

\(P=\frac{B^{2}L^{2}v}{R}\times v=\frac{B^{2}L^{2}v^{2}}{R}\)

Answer:

\(\frac{B^{2}L^{2}v^{2}}{R}\)