Figure \(\mathrm{P} 27. 33\) shows the arrangement we looked at in Example 27. 2: a metal bar \(0.20 \mathrm{~m}\) long suspended from two springs, cach having a spring constant \(k=0.10 \mathrm{~N} / \mathrm{m}\). Initially there is no current through the bar, and it is suspended at rest below the ceiling. With a current of \(0.45 \mathrm{~A}\), the bar rises a distance \(d=1.5 \mathrm{~mm}\). Suppose that the current is turned off, the bar drops down to its original position, and we attach a \(5.0-\mathrm{mg}\) piece of plastic to the center of the bar. Now how much current must there be through the bar to make it rise a distance \(d=1.5 \mathrm{~mm} ?

Data from Figure P27.33

Data from Example 27. 2

A metal bar \(0.20 \mathrm{~m}\) long is suspended from two springs, each with spring constant \(k=0.10 \mathrm{~N} / \mathrm{m}\), and the bar is in an external magnetic field directed perpendicular to the bar length (Figure 27.33). With a current of \(0.45 \mathrm{~A}\) in the bar, the bar rises a distance \(d=1.5 \mathrm{~mm}\).

Transcribed Image Text:

k=0.10 N/m d = 1.5 mm B into page I = 0.45 A -0.20 m x x k = 0.10 N/m