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# Machine Design - 2

## 20 Questions MCQ Test Mock Test Series for SSC JE Mechanical Engineering | Machine Design - 2

Description
This mock test of Machine Design - 2 for SSC helps you for every SSC entrance exam. This contains 20 Multiple Choice Questions for SSC Machine Design - 2 (mcq) to study with solutions a complete question bank. The solved questions answers in this Machine Design - 2 quiz give you a good mix of easy questions and tough questions. SSC students definitely take this Machine Design - 2 exercise for a better result in the exam. You can find other Machine Design - 2 extra questions, long questions & short questions for SSC on EduRev as well by searching above.
QUESTION: 1

### The important factor to be considered while selecting a bearing is

Solution:

Important factors to be considered:

(1) Dimensional limitation: Allowable space for bearings is generally limited.

(2) Applied loads: The characteristic, magnitudes & direction of loads is important.

(3) Rotational speed: It depends upon bearing type, size, tolerance, cage type, load lubrication & cooling condition,

(4) Bearing tolerances

(5) Rigidity

(6) Misalignment of inner & outer races

(7) Noise & torque levels

(8) Installation of disassembly.

QUESTION: 2

### Rivet nominal pitch is:

Solution:

Pitch is the distance between two adjacent rows of rivet parallel to the direction of application of force. The minimum pitch will be 2.5 times the gross diameter.

Minimum pitch should not be less than 2.5 times the nominal diameter of the rivet.

As a thumb rule pitch equal to 3 times the nominal diameter of the rivet is adopted.

Maximum pitch shall not exceed 32 times the thickness of the thinner outside plate or 300 mm whichever is less.

QUESTION: 3

### The frictional torque transmitted by a cone clutch is same as:

Solution:

QUESTION: 4

Function of cage in ball bearing is:

Solution:

In a single row deep grove ball bearing, caves are needed to ensure that the balls do not cluster at one point (i.e. to maintain the balls at a fixed distance apart) and maintain proper relative angular motion.

QUESTION: 5

The ‘Crowning’ of the flat pulley is generally done:

Solution:

The rim of the pulley of a flat belt drive is slightly crowned to prevent the slipping off the belt from the pulley.

QUESTION: 6

Solution:

QUESTION: 7

A key that has curved bottom to match the shaft. This key is known as________

Solution:

The sunk keys are provided half in the keyway of the shaft and half in the keyway of the hub or boss of the pulley.

A key attached to one member of a pair and which permits relative axial movement is known as feather key. It is a special type of parallel key which transmits a turning moment and permits axial movement.

flat saddle key is a taper key which fits in a keyway in the hub and is flat on the shaft. It is likely to slip round the shaft under load. Therefore, it is used for comparatively light loads.

hollow saddle key is a taper key which fits in a keyway in the hub and the bottom of the key is shaped to fit the curved surface of the shaft. Since hollow saddle keys hold on by friction, therefore these are suitable for light loads. It is usually used as a temporary fastening in fixing and setting eccentrics, cams etc.

QUESTION: 8

The included angle in Acme threads is

Solution:

Thread angle or included angle = 29°

They are generally used in screw-cutting lathes

QUESTION: 9

Which of the following is an absorption type dynamometer ?

Solution:

A dynamometer is a device used for measuring the torque and brake power required to operate a driven machine. It has a device to measure the frictional resistance.

Following are the two types of dynamometers, used for measuring the brake power of an engine.

1. Absorption dynamometers: The entire energy or power produced by the engine is absorbed by the friction resistances of the brake and is transformed into heat, during the process of measurement.

Example: Prony brake dynamometer, Rope brake dynamometer, Hydraulic dynamometer

2. Transmission dynamometers: The energy is not wasted in friction but is used for doing work. The energy or power produced by the engine is transmitted through the dynamometer to some other machines where the power developed is suitably measured.

Example: Epicyclic-train dynamometer,  Belt transmission dynamometer, Torsion dynamometer.

QUESTION: 10

The head for boiler applications shown in the figure given below is:

Solution:

QUESTION: 11

Which of the following is Trapezoidal thread?

Solution:
QUESTION: 12

Which if the following key is under compression rather than in being shear when under load?

Solution:

A key is a machine member employed at the interface of a pair of mating male and female circular cross-sectioned members to prevent relative angular motion between these mating members. The key fits into mating grooves in the shaft and mating member called the keyway and transmit torque by shear across the key.

Barth key is a modification of rectangular key which has two beveled surfaces. The beveled surface ensures that the key will fit tightly. This key is usually under compression rather than shear.

QUESTION: 13

Ball bearing type screws are found in following application

Solution:

Ball screw is also called as ball bearing screw or recirculating ballscrew. It is a mechanical linear actuator that translates rotational motion to linear motion with little friction. It consists of a screw spindle, a nut, balls and integrated ball return mechanism.

Ball screws are used in aircraft and missiles to move control surfaces, and in automobile power steering to translate rotary motion from an electric motor to axial motion of the steering rack. They are also used in machine tools, robots and precision assembly equipment.

QUESTION: 14

The crest diameter of a screw thread is same as _____

Solution:

Screw thread is a continuous helical groove of specified cross-section produced on the external or internal surface. A screw thread formed on a cylinder is known as straight or parallel screw thread, while screw thread formed on a cone or frustum is known as the tapered screw thread.

Crest: Crest of the thread is the top most surface joining the two sides.

Root: Root of the thread is the bottom of the groove between the two flanks.

Pitch: Pitch of a thread is the distance measured parallel to the axis from a point on a thread to the corresponding points on adjacent thread forms in the same axial plane and on the same side of the axis.

Major diameter: It is an imaginary largest diameter of the thread which would touch the crests of an internal or external thread. It is also called crest diameter.

Minor diameter: It is an imaginary smallest diameter of the thread which would touch the roots of an external thread.

Pitch diameter: It is a theoretical diameter between the major and minor diameter of screw threads.

QUESTION: 15

Which key transmits power through frictional resistance only

Solution:

Saddle key is a key that fits in the key way of the hub only. In this case there is no keyway provided on the shaft and friction between shaft, key and hub prevents relative motion between the shaft and the hub and power is transmitted by means of friction only.

QUESTION: 16

In a plate clutch axial force is 4 kN. The inside radius of contact surface is 50 mm and the outside radius is 100 mm. For uniform pressure the mean radius of friction surface will be

Solution:

For Uniform pressure theory

For Uniform wear theory the mean radius of friction surface is given as

QUESTION: 17

The centre to centre distance between two consecutive rivets in a row is called

Solution:

Pitch: This is the distance between two centres of the consecutive rivets in a single row.

Back Pitch: This is the shortest distance between two successive rows in a multiple riveted joint.

Diagonal pitch: This is the distance between the centers of rivets in adjacent rows of zigzag riveted joint.

Margin or marginal pitch: This is the distance between the centre of the rivet hole to the nearest edge of the plate.

QUESTION: 18

For longitudinal joint in boiler, the type of joint used is

Solution:

The longitudinal joint in a boiler shell is usually Butt joint with two cover plates this joint is more efficient than lap joint. It is also stiffer and helps to maintain circularity of the shell.

QUESTION: 19

A Hook’s joint is used to connect

Solution:

A Hook’s joint, commonly known as a universal joint is used to connect two non-parallel and intersecting shafts. It is also used for shafts with angular misalignment. A common application of this joint is in an automobile where it is used to transmit power from the gear box (of the engine) to the real axle.

QUESTION: 20

If for steel pinion BHN is 350 the value of load stress factor is

Solution: