Question

b

Consider the following (washing machine) 100-turn loop. The current running through it is 1-8.04, and there is a magnetic field of strength B- 0.70-T oriented out of page II. 8.0 cm 100-turn coil Area 64 cm2 8.0 cm What is the maximum torque generated on this coil? a. b. If we could sustain this maximum torque (using a slightly different geometry), how long would it take to accelerate a drum with moment of inertia radians/sec? 20 kgm2 up to an angular speed of 2.0

Answer 1

N = 100 turns, I = 8 A, Area A = 64 cm^2 = 64 times 10^-4 m^2 B = 0.70 T Torque is given by T = NIBA sin A so T_max = NIBA T_max = 100 times 8 times 0.70 times 64 times 10^-4 T_max = 3.584 N - m because T = I alpha implies alpha = T_max/I implies alpha = 3.584/20 (because I = 20 kg m^2) implies alpha = 0.1792 rad/s^2 Now, using eqn of motion, w = w_0 + alpha t w_0 = 0 rad/s, w = 2 rad/s, alpha = 0.1792 rad/s^2 so implies 2 = 0 + 0.1792 t implies t = 11.165 Ans