223) Whitworth quick return motion mechanism is an inversion of a double slider crank chain.

224) The maximum gyroscopic couple acting on the ship tends to shear the holding down bolts.

225) In a multiple V-belt drive, when a single belt is damaged, it is preferable to change the complete set to

226) A force acting in the opposite direction to the motion of the body is called force of friction.

227) A shaft has two heavy rotors mounted on it. The transverse natural frequencies, considering each of the rotor separately, are 100 Hz and 200 Hz respectively. The lowest critical speed is