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

228) Torsional vibrations are said to occur when the particles of a body moves

229) A body is said to vibrate with simple harmonic motion if its acceleration is proportional to the distance from the mean position.