Q. A small metal ball, carrying a net charge of q_1 = -2.70 mu C, is held in a stationary position by insulating supports. A second small metal ball, with a net charge of q_2 = -7.20 mu C and mass 1.70 g, is projected toward q_{1}. When the two spheres are 0.800 rm m apart, q_{2} is moving toward q_{1} with speed 22.0 rm m/s . Assume that the two spheres can be treated as point charges. You can ignore the force of gravity.What is the speed of q_{2} when the balls are 0.450 m apart?
Q. A 0.75 meter long metal bar is released from rest. It is connected to the circut as shown which is positioned in a magnetic field of 4.3 T. After a very short distance the bar falls at a constant speed.
A. If the bar has a mass of 4 kg what current must be induced on the circuit?
B. Given that the resistor is 6 ohlms, what is the speed that the bar falls?