When two springs are in series (having stiffness K), the equivalent stiffness will be
K
K/2
2K
K/4
Correct Answer :
B. K/2
Related Questions
The ratio of circumferential stress to longitudinal stress in a thin cylinder subjected to an internal pressure is
½
1
2
4
A fast and loose pulley drive is used when
Shafts are arranged parallel and rotate in the opposite directions
Shafts are arranged parallel and rotate in the same directions
Shafts are arranged at right angles and rotate in one definite direction
Driven shaft is to be started or stopped whenever desired without interfering with the driving shaft
In a belt drive, if the pulley diameter is doubled keeping the tension and belt width constant, then it will be necessary to
Increase the key length
Increase the key depth
Increase the key width
Decrease the key length
Wahl's stress factor __________ very rapidly as the spring index decreases.
Increases
Decreases
Remain same
None of these
For circumferential joint in boilers, the type of joint used is
Butt joint with single cover plate
Butt joint with double cover plate
Lap joint with one ring overlapping the other
Any one of the above
The size of a cam depends upon
Base circle
Pitch circle
Prime circle
Pitch curve
If a shaft made from ductile material is subjected to combined bending and twisting moment, calculations based on which one of the following failure theories will give the most conservative value?
Maximum principal stress theory
Maximum shear stress theory
Maximum strain energy theory
Maximum distortion energy theory
The shear stress at a point in a shaft subjected to a torque is
Directly proportional to the polar moment of inertia and to the distance of the point from the axis
Directly proportional to the applied torque and inversely proportional to the polar moment of inertia
Directly proportional to the applied torque and the polar moment of inertia
Inversely proportional to the applied torque and the polar moment of inertia
A machine part subjected to __________ is called a strut.
An axial compressive force
A tangential force
An axial tensile force
Any one of these
Which of the following screw thread is adopted for power transmission in either direction?
Acme threads
Square threads
Buttress threads
Multiple threads
In designing a flange coupling, the pitch circle diameter of bolts is taken as (where d = Diameter of the shaft)
2d
3d
4d
5d
In static loading, stress concentration is more serious in
Brittle materials
Ductile materials
Brittle as well as ductile materials
Elastic materials
The coefficient of friction between the belt and pulley depends upon the
Material of belt and pulley
Slip of belt
Speed of belt
All of these
In a multiple V-belt drive, if one of the belts break, then
Only the broken belt is replaced
The entire set of belts is replaced
The broken belt and the belt on either side of it, is replaced
The broken belt need not to be replaced
Tapered roller bearings can take
Axial load only
Both radial and axial loads and the ratio of these being greater than unity
Radial load only
Both radial and axial loads and the ratio of these being less than unity
The wire ropes make contact at
Bottom of groove of the pulley
Sides and bottom of groove of the pulley
Anywhere in the groove of the pulley
Sides of groove of the pulley
A triple riveted butt joint with double straps of unequal width is to be designed for a boiler shell. The pitch of the rivets in the outer row is double the pitch in the inner row and zigzag riveting is proposed. Which of the following statement is correct?
There are four rivets per pitch length, all in double shear
There are four rivets per pitch length, out of which two are in single shear and two are in double shear
There are five rivets per pitch length, all in double shear
There are five rivets per pitch length, out of which four are in double shear and one is in single shear
The static tooth load should be __________ the dynamic load.
Equal to
Less than
Greater than
None of these
The power transmitted by belt drive depends upon
Belt velocity
Initial belt tension
Arc of contact
All of the above
The expression 0.175 - 0.841/T is the Lewis form factor for
14 ½° composite and full depth involute system
20° full depth involute system
20° stub system
None of the above
According to Indian standards, the diameter of rivet hole is made larger than the basic size of rivet by
0.5 mm upto rivet diameter of 24 mm
1 mm for rivet diameter from 27 mm to 36 mm
2 mm for rivet diameter from 39 mm to 48 mm
All of the above
Cold working
Increases the fatigue strength
Decreases the fatigue strength
Has no influence on fatigue strength
Alone has no influence on fatigue strength
The crest diameter of a screw thread is same as
Major diameter
Minor diameter
Pitch diameter
Core diameter
Spring index is
Ratio of coil diameter to wire diameter
Load required to produce unit deflection
Its capability of storing energy
Indication of quality of spring
The taper on key is given on
Bottom side only
Top side only
On both sides
Any side
The design calculations for members subject to fluctuating loads with the same factor of safety, yield the most conservative estimates when using
Gerber relation
Soderberg relation
Goodman relation
None of these
The taper on a rectangular sunk key is
1 in 16
1 in 32
1 in 48
1 in 100
The bearings of heavy series have capacity ________ over the medium series.
20 to 30%
10 to 20%
30 to 40%
40 to 50%
The designation M 33 × 2 of a bolt means
Metric threads of 33 numbers in 2 cm
Metric threads with cross-section of 33 mm
Metric threads of 33 mm outside diameter and 2 mm pitch
Bolt of 33 mm nominal diameter having 2 threads per cm
Which of the following is a permanent fastening?
Bolts
Keys
Cotters
Rivets