A conducting rod with length 0.221 mm , mass 0.140 kgkg , and resistance 79.6 ΩΩ moves without friction on metal rails as shown in the following figure(Figure 1). A uniform magnetic field with magnitude 1.50 TT is directed into the plane of the figure. The rod is initially at rest, and then a constant force with magnitude 1.90 NN and directed to the right is applied to the bar.How many seconds after the force is applied does the bar reach a speed of 20.8 m/sm/s ?