Mechanics & Strength of Materials 6

Objective Questions and Answer: Mechanics & Strength of Materials 6

Subject:  Mechanics & Strength of Materials 6

Part 6: Objective questions and answers of Mechanics & Strength of Materials

Q1. According to principle of moments

a) If a system of coplanar forces is in equilibrium, then their algebraic sum is zero

b) If a system of coplanar forces is in equilibrium, then the algebraic sum of their moments about any point in their plane is zero

c) The algebraic sum of the moments of any two forces about any point is equal to moment of the resultant about the same point

d) Positive and negative couples can be balanced

Q2. Which of the following is not a vector quantity?

a) Weight

b) Velocity

c) Acceleration

d) Force

Q3. According to law of triangle of forces

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

Q4. If a rigid body is in equilibrium under the action of three forces, then

a) These forces are equal

b) The lines of action of these forces meet in a point

c) The lines of action of these forces are parallel

d) (b) and (c) above

Q5. D Alembert′s principle is used for

a) Reducing the problem of kinetics to equivalent statics problem

b) Determining stresses in the truss

c) Stability of floating bodies

d) Designing safe structures

Q6. A heavy ladder resting on floor and against a vertical wall may not be in equilibrium, if

a) The floor is smooth, the wall is rough

b) The floor is rough, the wall is smooth

c) The floor and wall both are smooth surfaces

d) The floor and wall both are rough surfaces

Q7. 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

Q8. Two coplanar couples having equal and opposite moments

a) Balance each other

b) Produce a couple and an unbalanced force

c) Are equivalent

d) Can not balance each other.

Q9. A framed structure is perfect if it contains members equal to

a) 2n-3

b) N-l

c) 2n-l

d) N – 2where n = number of joints in a frame

Q10. 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

Q11. In determining stresses in frames by methods of sections, the frame is divided into two parts by an imaginary section drawn in such a way as not to cut more than

a) Two members with unknown forces of the frame

b) Three members with unknown forces of the frame

c) Four members with unknown forces of the frame

d) Three members with known forces of the frame

Q12. 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 the above

Q13. 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

Q14. 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

Q15. 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

Q16. The center of percussion of the homogeneous rod of length L suspended at the top will be

a) L/2

b) L/3

c) 3L/4

d) 2L/3

Q17. 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

a) Compression or tension

b) Buckling or shear

c) Shear or tension

d) All of the above

Q19. 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

Q20. 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) 2.5 cm

b) 3.0 cm

c) 4.0 cm

d) 5.0 cm

Part 6: Objective questions and answers of Mechanics & Strength of Materials