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Free download in PDF Machine Kinematics Multiple Choice Questions and Answers for competitive exams. These short objective type questions with answers are very important for Board exams as well as competitive exams like UPSC, NDA, SSC etc. These short solved questions or quizzes are provided by Gkseries./p>
(1)
In a squared and ground helical spring the effective number of turns is increased by
[A]
1
[B]
2
[C]
1.5
[D]
0
(2)
Frequency of the fluctuating load on a helical compression spring should be
[A]
less than natural frequency of vibration
[B]
twenty times the natural frequency of vibration
[C]
slightly greater than the natural frequency
[D]
twenty times the natural frequency of vibration
Answer: twenty times the natural frequency of vibration
(3)
Two concentric springs with stiffness equal to 100 N/mm and 80 N/mm respectively, when subjected to a load of 900 N will deflect by
[A]
9 mm
[B]
11.25 mm
[C]
5 mm
[D]
31.5 mm
(4)
Stiffness of the spring can be increased by
[A]
increasing the number of turns
[B]
increasing the free length
[C]
decreasing the number of turns
[D]
decreasing the spring wire diameter
Answer: decreasing the number of turns
(5)
The stress induced in an extra full length leaf in case of a prestresed leaf spring is
[A]
1.5 times that in graduated leaves
[B]
equal to that in graduated leaves
[C]
dependent on the ratio of the number of extra full length and graduated leaves
[D]
none of the mentioned
Answer: equal to that in graduated leaves
(6)
Initial gap between two turns of a close coiled helical tension spring should be
[A]
0.5 mm
[B]
based on the maximum deflection
[C]
1 mm
[D]
0
(7)
Due to addition of extra full length leaves the deflection of a semi-elliptic spring
[A]
increases
[B]
decreases
[C]
does not change
[D]
is doubled
(8)
A connecting rod of mass 5.5 kg is placed on a horizontal platform whose mass is 1.5 kg. It is suspended by three equal wires, each 1.25 m long, from a rigid support. The wires are equally spaced round the circumference of a circle of 125 mm radius. When the c.g. of the connecting rod coincides with the axis of the circle, the platform makes 10 angular oscillations in 30 seconds. Determine the mass moment of inertia about an axis through its c.g.
[A]
0.198 kg-m2
[B]
1.198 kg-m2
[C]
2.198 kg-m2
[D]
3.198 kg-m2
(9)
In order to find the radius of gyration of a car, it is suspended with its axis vertical from three parallel wires 2.5 metres long. The wires are attached to the rim at points spaced 120° apart and at equal distances 250 mm from the axis. It is found that the wheel makes 50 torsional oscillations of small amplitude about its axis in 170 seconds. Find the radius of gyration of the wheel.
[A]
168 mm
[B]
268 mm
[C]
368 mm
[D]
468 mm
(10)
A small connecting rod of mass 1.5 kg is suspended in a horizontal plane by two wires 1.25 m long. The wires are attached to the rod at points 120 mm on either side of the centre of gravity. If the rod makes 20 oscillations in 40 seconds, find the radius of gyration of the rod about a vertical axis through the centre of gravity.
[A]
107 mm
[B]
207 mm
[C]
307 mm
[D]
407 mm
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