Machine Design MCQs

Question 1

When a material is subjected to fatigue loading, the ratio of the endurance limit to the ultimate tensile strength is

Accepted Answer

0.5

Answer

0.2

Answer

0.35

Answer

0.65

Question 2

The centrifugal tension in the belt

Accepted Answer

Has no effect on the power transmitted

Answer

Increases the power transmitted

Answer

Decreases the power transmitted

Answer

Is equal to maximum tension on the belt

Question 3

A long helical spring having a spring stiffness of 12 kN/m and number of turns 20, breaks into two parts with number of turns 10 each in both the parts. If the two parts are connected in series, then the softness of the resultant spring will be

Accepted Answer

12 kN/m

Answer

6 kN/m

Answer

24 kN/m

Answer

30 kN/m

Question 4

In a band and block brake, the ratio of tensions on the tight and slack sides of band is given by (where $$\mu $$ = Coefficient of friction between the blocks and the drum, $$	heta $$ = Semi-angle of each block subtending at the centre of drum and n = Number of blocks)

Accepted Answer

$$\frac{{{{	ext{T}}_1}}}{{{{	ext{T}}_2}}} = {\left( {\frac{{1 + \mu 	an 	heta }}{{1 - \mu 	an 	heta }}} ight)^{	ext{n}}}$$

Answer

$$\frac{{{{	ext{T}}_1}}}{{{{	ext{T}}_{	ext{2}}}}} = \mu 	heta 	imes {	ext{n}}$$

Answer

$$\frac{{{{	ext{T}}_1}}}{{{{	ext{T}}_2}}} = {\left( {\mu 	heta } ight)^{	ext{n}}}$$

Answer

$$\frac{{{{	ext{T}}_1}}}{{{{	ext{T}}_2}}} = {\left( {\frac{{1 - \mu 	an 	heta }}{{1 + \mu 	an 	heta }}} ight)^{	ext{n}}}$$

Question 5

Slenderness ratio is the ratio of

Accepted Answer

Effective length of column to least radius of gyration of the column

Answer

Width of column to depth of column

Answer

Maximum size of column to minimum size of column

Answer

Effective length of column to width of column

Question 6

The contact ratio is the ratio of

Accepted Answer

Length of arc of contact to the circular pitch

Answer

Length of arc of recess to the circular pitch

Answer

Length of path of contact to the circular pitch

Answer

Length of arc of approach to the circular pitch

Question 7

A pressure vessel is said to be a thick shell, if the ratio of wall thickness to its diameter is

Accepted Answer

Greater than $$\frac{1}{{10}}$$

Answer

Equal to $$\frac{1}{{10}}$$

Answer

Less than $$\frac{1}{{10}}$$

Answer

None of these

Question 8

The pitch of threads on a Jock nut in comparison to pitch of nut is

Accepted Answer

Same

Answer

Coarser

Answer

Finer

Answer

Very fine

Question 9

In hydrodynamic bearings

Accepted Answer

The oil film pressure is generated only by the rotation of the journal

Answer

The oil film is maintained by supplying oil under pressure

Answer

Do not require external supply of lubricant

Answer

Grease is used for lubrication