I have absolutely no idea how to do any part of this problem, can anyone help? 7. A group of students, working in the physics lab, built an “Electromagnetic Vertical Launcher”. The apparatus includes an electric circuit with a 120 V battery, connected in series to a 100 Ω resistor, switch, and thin 500 g metallic rod that is placed on two horizontal conducting supports. The rod has a length of 40 cm and is placed in a uniform horizontal 1.5 T strong magnetic field. a). On the diagram below show all the applied forces on the rod when the switch is closed. b). Find the normal force in each support when the switch is closed. c). What is the minimum voltage has to be applied in order to keep the rod weightless? d). The resistor is replaced with much smaller value of 5 Ω resistor. When the switch is closed find the instantaneous acceleration of the rod.