In an epicyclic gear train, the sun gear on the input shaft is 20 teeth external gear. The planet gear is a 40 teeth external gear and the ring gear is a 100 teeth internal gear. The ring gear is fixed and the sun gear is rotating at 60 rpm counter clockwise. The arm attached to output shaft will rotate at ________
(a) 5 rpm
(b) 10 rpm
(c) 20 rpm
(d) 30 rpm
The question was asked in a job interview.
This intriguing question comes from Mechanical Power Transmission in chapter Mechanical Power Transmission of Farm Machinery