Engineering Mechanics objective questions with answers part1

Q1. According to Lami’s theorem
(A) three forces acting at a point will be in equilibrium
(B) three forces acting at a point can be represented by a triangle, each side being proportional to force
(C) if three forces acting upon a particle are represented in magnitude and direction by the sides of a triangle, taken in order, they will be in equilibrium
(D) if three forces acting at a point are in equilibrium, each force is proportional to the sine of the angle between the other two

Q2. Two coplanar couples having equal and opposite moments
(A) balance each other
(B) produce a couple and an unbalanced force
(C) produce a moment of couple
(D) can not balance each other

Q3. The product of either force of couple with the arm of the couple is called
(A) resultant couple
(B) moment of the forces
(C) resulting couple
(D) moment of the couple

Q4. The center of gravity of a uniform lamina lies at
(A) the center of heavy portion
(B) the bottom surface
(C) the mid point of its axis
(D) All of these

Q5. Center of gravity of a solid cone lies on the axis at the height
(A) one-fourth of the total height above base
(B) one-third of the total height above base
(C) one-half of the total height above base
(D) three-eighth of the total height above the base

Q6. Center of percussion is
(A) the point of C.G.
(B) the point of metacentre
(C) the point of application of the resultant of all the forces tending to cause a body to rotate about a certain axis
(D) point of suspension

Q7. Center of gravity of a thin hollow cone lies on the axis at a height of
(A) one-fourth of the total height above base
(B) one-third of the total height above base
(C) one-half of the total height above base
(D) three-eighth of the total height above the base

Q8. The center of percussion of the homogeneous rod of length L suspended at the top will be
(A) L/6
(B) L/3
(C) 3L/4
(D) 2L/3

Q9. The center of gravity of a triangle lies at the point of
(A) concurrence of the medians
(B) intersection of its altitudes
(C) intersection of bisector of angles
(D) intersection of diagonals

Q10. The possible loading in various members of framed structures are
(A) compression or tension
(B) buckling or shear
(C) shear or tension
(D) All of these

Q11. A heavy string attached at two ends at same horizontal level and when central dip is very small approaches the following curve
(A) catenary
(B) parabola
(C) hyperbola
(D) elliptical

Q12. A trolley wire weighs 1.2 kg per meter length. The ends of the wire are attached to two poles 20 meters apart. If the horizontal tension is 1500 kg find the dip in the middle of the span
(A) 3.5 cm
(B) 3.0 cm
(C) 4.0 cm
(D) 6.0 cm

Q13. From a circular plate of diameter 6 cm is cut out a circle whose diameter is a radius of the plate. Find the e.g. of the remainder from the center of circular plate
(A) 0.5 cm
(B) 2.0 cm
(C) 3.5 cm
(D) 2.5 cm

Q14. Pick up the incorrect statement from the following :
(A) The C.G. of a circle is at its center
(B) The C.G. of a triangle is at the intersection of its medians
(C) The C.G. of a rectangle is at the inter-section of its diagonals
(D) The C.G. of a semicircle is at a distance of r/2 from the center

Q15. The center of percussion of a solid cylinder of radius r resting on a horizontal plane will be
(A) r/6
(B) 2r/3
(C) r/A
(D) 3r/2

Q16. In the equation of virtual work, following force is neglected
(A) reaction of any smooth surface with which the body is in contact
(B) reaction of a rough surface of a body which rolls on it without slipping
(C) reaction at a point or an axis, fixed in space, around which a body is con-strained to turn
(D) All of these

Q17. If a suspended body is struck at the center of percussion, then the pressure on die axis passing through the point of suspension will be
(A) maximum
(B) minimum
(C) zero
(D) infinity

Q18. The resultant of the following three couples 20 kg force, 0.5 m arm, $ ve sense 30 kg force, 1 m arm, - ve sense 40 kg force, 0.25 m arm, + ve sense having arm of 0.5 m will be
(A) 20 kg, negative sense
(B) 20 kg, positive sense
(C) 10 kg, positive sense
(D) 10 kg, negative sense

Q19. Angle of friction is the
(A) angle between normal reaction and the resultant of normal reaction and the limiting friction
(B) ratio of limiting friction and normal reaction
(C) the ratio of minimum friction force to the friction force acting when the body is just about to move
(D) the ratio of minimum friction force to friction force acting when the body is in motion

Q20. The coefficient of friction depends on
(A) area of contact
(B) shape of surfaces
(C) strength of surfaces
(D) nature of surface