Question

m, RU B2 8. An adjustable loop, with a cross-bar of width w that slides between two rails, is tilted so that it makes an angle with respect to the ground. Let the sliding cross-bar have a resistance R and a mass m (and neglect any other resistance). a. If the loop is placed in a vertical magnetic field, B = Bỉ, show that the cross-bar does not keep accelerating, but reaches a terminal speed mgR sine B2w2 cos20 V = b. If the cross-bar is sliding at a constant speed, its kinetic energy is not changing. Yet it is still falling. Where is the gravitational potential energy going

Answer 1

e-moving Bar (has mops = m) mg sino ang ng " O side view of moving Bar experiance a (mg sino force on inclined plane . moving Bar is matellic bar hence have free electrons and as we know that when free charge moving in magnetic feld eb expenance a Forced =.g (V x B ) mars Because of this current start flowing in the loop and we also know ridat when current carrying conductor is placed in a magnetic field it experiance a force = 7 (EXB) AB i LEXB) = opposite to --velocity 0 inword current flouding Añ

- Bar hence force : is moving with a constant velocit FB in Balanced By gravitational CA - Fe = mg sino i (LB) = mg sino I » Do 9 E=9UB con in equilibrin u = hasie Ha . # charge seperation Due to magnetic force - on mening charges و Va Beoso = VB coso 4 dp is e. speed 1 E = VB cose . EMFE E We i = current = EMA E VB Cosow . g n t = Bar length = w El B = ng sino VB coso w x W x B = mg 12 .. sno - mq sino R 33. 3 се - - -- - - - - magnetic force on the bar is opposite to the velocity and bar is sliding down thats with a konstant KE This means reduction in Potential Energy is going to a Balance the magnetic force which oppose the Bar motion on plene -