A conducting rod with length 0.169 m , mass 0.120 kg, and resistance 81.3 2 moves without friction on metal rails as shown in the following figure(Figure 1). Auniform magnetic field with magnitude 1.50 T is directed into the plane of the figure. The rod is initially at rest, and then a constant force with magnitude 1.90 N and directed to the right is applied to the bar. Part A How many seconds after the force is applied does the bar reach a speed of 20.4 m/s ? Express your answer with the appropriate units.

A conducting rod with length 0.169 m , mass 0.120 kg, and resistance 81.3 2 moves without friction on metal rails as shown in the following figure(Figure 1). Auniform magnetic field with magnitude 1.50 T is directed into the plane of the figure. The rod is initially at rest, and then a constant force with magnitude 1.90 N and directed to the right is applied to the bar. Part A How many seconds after the force is applied does the bar reach a speed of 20.4 m/s ? Express your answer with the appropriate units.