Aconducting bar slides without friction on two parallel horizontal rails that are 50 cm apart and connected by a wire at oneend. the resistance of the bar and the rails is constant and equal to 0.10 ω. a uniform magnetic field is perpendicular to theplane of the rails. a 0.080-n force parallel to the rails is required to keep the bar moving at a constant speed of 0.50 m/s. whatis the magnitude of the magnetic field?
a. 0.36 tb. 0.10 tc. 0.54 td. 0.93 te. 0.25 t

You are the coordinator for a program that is going to take place at night in a rectangular amphitheater in the mountains. you will have no access to any electricity, but you must be able to illuminate the entire grounds. you know the intensity of the light from a lantern varies inversely as the square of the distance from the lantern. suppose the intensity is 90 when the distance is 5 m. a. write an equation to model the situation. b. solve for the constant of variation. c. write the equation to model the situation using the constant () of variation. d. you have been given lanterns with 40 light intensity. use your equation to solve for the distance from the lantern. e. you need to illuminate 225 km. how many meters do you need to light? f. how many lanterns will you need?