Question

W W U LU DLM DULI TULUI 12.01.00 A LU was II I. TIM Cuu wa ITVIY TE (17%) Problem 2: A fan has four blades attached to a central shaft. The blades are le 12 cm long and each blade have a uniformly distributed mass of me = 0.19 kg. The fan spins up from rest to an angular speed of oy - 111 rad/s in 0.85 s. ted W33% Part(a) Treat each fan blade as a uniform rod of length le rotating about its end, Enter an expression for the total change in the momentum AL of the fan during the spin up. Assume the angular momentum of the central shaft is insignificant. Grade Sun AL= Deductions Potential Late Work B AL ( 7 8 9 Partial 2 3 ON Submissions Amemperem VO BACKSPACE CLEAR detailed view Submit Hint Feedback I give up! Hints: 4% deduction per hint. Hints remaining 2 Feedback: 55 deduction per feedback. A 33% Part (b) Give an expression for the average torque Tr that the fan's motor exerts on the fan as it spins up. A 33% Part (e) If the fan spins through 7.5 rotations during the spin up, calculate the work Win joules, that the fan's motor does on the fan.

Answer 1

- 6 moment of thentia of one fan blade I = 1/2 male? Tatal moment of inentin If I mfft? Change in angular momentum. AL= Is Wf- To u = 3 , 4 , -0 DL= f (me le+ (4) o Taque (average) z dhe Tang - Al 1 = 4 4 Lang - (hep 4 mont) © Tag = $x 0.19% (0-12,3 x work, W = Targ O = 0.4763+(1.5X24) 0.85 0.4763 No = 22.47