161. When there is a reduction in amplitude over every cycle of vibration, then the body is said to have
free vibration
forced vibration
damped vibration
under damped vibration
✅ The correct answer is option C.
Theory of machines MCQs
162. The unbalanced force due to reciprocating masses
varies in magnitude but constant in direction
varies in direction but constant in magnitude
varies in magnitude and direction both
constant in magnitude
✅ The correct answer is option A.
163. Which of the following statement is correct for involute gears?
The interference is inherently absent.
The variation in centre distance of shafts increases radial force.
A convex flank is always in contact with concave flank.
The pressure angle is
✅ The correct answer is option D.
165. A friction circle is a circle drawn when a journal rotates in a bearing. Its radius depends upon the coefficient of friction and the
magnitude of the forces on journal
angular velocity of journal
clearance between journal and bearing
radius of journal
✅ The correct answer is option D.
166. The acceleration of a flat-faced follower when it has contact with the flank of a circular arc cam, is given by
ω2R cos θ
ω2(R – r1)cos θ
ω2(R – r1)sin θ
ω2r1 sin θ
✅ The correct answer is option B.
167. The natural frequency of free longitudinal vibrations is equal to (where m = Mass of the body, s = Stiffness of the body, and δ = Static deflection of the body)
any one of these
✅ The correct answer is option D.
168. The maximum frictional force, which comes into play, when an body just begins to slide over the surface of the other body, is known as
static friction
dynamic friction
limiting friction
coefficient of frictio
✅ The correct answer is option C.