Related Questions

While designing a screw in a screw jack against buckling failure, the end conditions for the screw are taken as
A both ends fixed
B both ends hinged
C one end fixed and other end hinged
D one end fixed and other end free.
John, Jack, Joseph and Jordan participated in a running race. Only the winner finished the race in 10 minutes. Which two pieces of information can tell you who the winner was? (i) John finished the race in 16 minutes . (ii) Joseph finished the race earlier than Jack by 2 minutes. (iii) Jack finished the race later than Jordan by 4 minutes. (iv) Jordan finished the race earlier than John by 6 minutes. (v) John finished the race later than Joseph by minutes.
A I and II
B I and IV
C II and III
D II and V
When the screw in a mechanical screw jack rotates, the load kept on the top of it moves
A Axially upwards
B Axially downwards
C Axially upwards or downwards
D None of these
Efficiency of a screw jack is given by (where $$\alpha $$ = Helix angle and $$\varphi $$ = Angle of friction.)
A $$\frac{{\tan \left( {\alpha + \varphi } \right)}}{{\tan \alpha }}$$
B $$\frac{{\tan \alpha }}{{\tan \left( {\alpha + \varphi } \right)}}$$
C $$\frac{{\tan \left( {\alpha - \varphi } \right)}}{{\tan \alpha }}$$
D None of these
The maximum efficiency of a screw jack is
A 1 – sinφ/ 1 + sinφ
B 1 + sinφ/ 1 – sinφ
C 1 – tanφ/ 1 + tanφ
D 1 + tanφ/ 1 – tanφ
The efficiency of a screw jack is maximum, when (where $$\alpha $$ = Helix angle and $$\varphi $$ = Angle of friction)
A $$\alpha = {45^ \circ } + \frac{\varphi }{2}$$
B $$\alpha = {45^ \circ } - \frac{\varphi }{2}$$
C $$\alpha = {90^ \circ } + \varphi $$
D $$\alpha = {90^ \circ } - \varphi $$
The efficiency of a screw jack is maximum, when (where $$\alpha $$ = Helix angle and $$\varphi $$ = Angle of friction.)
A $$\alpha = {45^ \circ } + \frac{\varphi }{2}$$
B $$\alpha = {45^ \circ } - \frac{\varphi }{2}$$
C $$\alpha = {90^ \circ } + \varphi $$
D $$\alpha = {90^ \circ } - \varphi $$
A screw is said to be over hauling screw, if its efficiency is
A less than 50%
B more than 50%
C equal to 50%
D none of the mentioned
A screw is said to be a self locking screw, if its efficiency is
A Less than 50%
B More than 50%
C Equal to 50%
D None of these
Jack is taller than Peter,and Bill is shorter than Jack.Which of the following statements would be most accurate?
A Bill is taller than Peter
B Bill is shorter than Peter
C Bill is as tall as Peter
D It is impossible to tell whether Bill or Peter is taller

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