Theory of machines Questions

• The pair is known as a higher pair, when the relative motion between the elements of a pair is
• In a screw jack, the effort required to lower the load W is given by
• When the connection between the two elements is such that only required kind of relative motion occurs, it is known as self-closed pair.
• In a circular arc cam with roller follower, the acceleration in any position of the lift will depend only upon
• The two links OA and OB are connected by a pin joint at O. If the link OA turns with angular velocity ω1 rad/s in the clockwise direction and the link OB turns with angular velocity ω2 rad/s in the clockwise direction, then the rubbing velocity at the pin joint O is (where r = Radius of the pin at O)
• The frequency of damped vibrations with viscous damping is __________ the frequency of undamped vibrations.
• In order to balance the reciprocating masses,
• An automobile steering gear is an example of
• The dynamic friction is the friction experienced by a body, when the body
• Whitworth quick return motion mechanism consists of three turning pairs and one sliding pair.
• When the two elements of a pair have a surface contact when relative motion takes place and the surface of one element slides over the surface of the other, the pair formed is known as a
• The swaying couple is maximum or minimum when the angle of inclination of the crank to the line of stroke (θ) is equal to
• The acceleration of the particle moving with simple harmonic motion is inversely proportional to the displacement of the particle from the mean position.
• The ratio of the actual damping coefficient to the critical damping coefficient is called damping factor.
• If ω/ωn is very high for a body vibrating under steady state vibrations, the phase angle for all values of damping factors, will tend to approach
• The tractive force in a locomotive with two cylinders is given by (where c = Fraction of reciprocating parts per cylinder, m = Mass of reciprocating parts, ω = Angular speed of crank, r = Radius of crank, and θ = Angle of inclination of crank to the line of stroke)
• In railway axle boxes, the bearing used is
• In order to give the primary balance of the reciprocating parts of a multi-cylinder in-line engines,
• When a particle moves round the circumference of a circle of radius r with ω rad/s, then its maximum acceleration is ω2r.
• The centre distance between two meshing involute gears is equal to