Question

03: (12.5 pts) The blade of an oscillating fan and the rotor of its motor have a total mass of 200 g and a combined radius of gyration of 75 mm as shown below. They are supported by bearings located at A and B, 125 mm apart, and have an angular velocity 01 of 2400 rpm at the high-speed setting. Determine the dynamic reactions at A and B when the motor casing has an angular velocity or of 0.5 rad/sec, where moment of inertia: I = mr2, r is the radius of gyration. Note: You must clearly label axes and must follow the course specific steps for solving the problem. j LE DROIT ERSITÉ D'OTTAWA MATERIAL UNIVERSITY OF OTTAWO 125 mm protected by copyi? have permission to upi you require clarification, B k - CONTEN D 2

Answer 1

ON We know, --> We = @ 21 (2400) 60 251.3 2 rad / Bec We Angular velocity: w. i + wî Angular Momentum : HE- Iz wit + Iy w Let the Seference frame be rotating bith angitor velocity 12 zwem + x Ha Ty w f) - Ix w. W Â Ha (Hala xyz o+w, i x( Ix Wq it Ha - negligible Seduce to Assume that the acceleration of the mass centre 18 Then the dynamic reactions at A and B a couple A = -B M- bix B bi xc By ſ + BLÂ) M - bbz + b by

M = Ha Resolve into Components. Az=0 Bz -b Bz j  : b By = – IzW, - Ix ww2 m kxw, w, By b Girene m = 0.200 kg Ka = 0.075m b= 0.125m > (0.200) (75X10-3)*x(251:32 ) 0.5) By 0.125 By - 1.130 N Ay - 1.130N A = ( 1.130 N) B = - - (1-130 N)