Mathematics

Problem

0.25\,\text{m}

long wire carries a current of

8\,\text{A}

. What minimum magnetic field strength, acting at

90^{\circ}

to the wire, is required so that the wire can just support an attached mass of

0.020\,\text{kg}

? Take

g = 9.8\,\text{m}\,\text{s}^{-2}