23. The planes of two rigid discs are perpendicular to each other. They are rotating about their axes. If their angular velocities are 3 rad/sec and 4 rad/sec respectively, then the resultant angular velocity of the system would be
(a) 1 rad/sec
(b) 7 rad/sec
(c) 5 rad/sec
(d) √12 rad/sec
Ans. c
(552)