1. The problem statement, all variables and given/known data A long, straight wire with linear mass density of 45g/m is suspended by threads, as shown in the figure . There is a uniform magnetic field pointing vertically downward. A 7.0A current in the wire experiences a horizontal magnetic force that deflects it to an equilibrium angle of 10 degree. What is the strength of the magnetic field B? 2. Relevant equations B=(U_o I) / (2 *3.14 * r) 3. The attempt at a solution I have U_0 given, I given. but can't find r. How can find r to get B?