Q 13. The rotor shaft of a large electric motor supported between short bearings at both deflection of 1.8mm in the middle of the rotor. Assuming the rotor to be perfectly balanced and supported at knife edges at both the ends, the likely critical speed (in rpm) of the shaft is
(A) 350
(B) 705
(C) 2810
(D) 4430
Answer: (B)
Explanation:
