27 real Engineering Mechanics questions from the Civil Core bank, as asked in Indian campus drives and tech interviews. Every question has a verified answer and an AI-tutor explanation on placd — free to start.
1. What is Lami's theorem?
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A.when three concurrent coplanar forces keep a body in equilibrium, each force is proportional to the sine of the angle between the other two
B.a dynamic problem is converted to an equivalent static one by adding an inertia force equal to mass times acceleration acting opposite to the acceleration
C.moment of a resultant about any point equals the algebraic sum of the moments of its component forces about that same point
D.ratio of limiting friction to normal reaction between two dry surfaces, independent of the apparent contact area
2. Which term means: "when three concurrent coplanar forces keep a body in equilibrium, each force is proportional to the sine of the angle between the other two"?
A.Lami's theorem — steepest inclination of a plane on which a body stays at rest under gravity alone, numerically equal to the angle of friction
B.Lami's theorem — moment of a resultant about any point equals the algebraic sum of the moments of its component forces about that same point
C.Lami's theorem — a dynamic problem is converted to an equivalent static one by adding an inertia force equal to mass times acceleration acting opposite to the acceleration
D.Lami's theorem — when three concurrent coplanar forces keep a body in equilibrium, each force is proportional to the sine of the angle between the other two
A.a system in equilibrium does zero net work under any small imaginary displacement compatible with its constraints, giving reactions and member forces without solving equilibrium equations
B.steepest inclination of a plane on which a body stays at rest under gravity alone, numerically equal to the angle of friction
C.moment of a resultant about any point equals the algebraic sum of the moments of its component forces about that same point
D.ratio of limiting friction to normal reaction between two dry surfaces, independent of the apparent contact area
A.Varignon's theorem — steepest inclination of a plane on which a body stays at rest under gravity alone, numerically equal to the angle of friction
B.Varignon's theorem — ratio of limiting friction to normal reaction between two dry surfaces, independent of the apparent contact area
C.Varignon's theorem — moment of a resultant about any point equals the algebraic sum of the moments of its component forces about that same point
D.Varignon's theorem — moment of inertia about any axis equals that about the parallel centroidal axis plus area times the square of the distance between the axes
A.when three concurrent coplanar forces keep a body in equilibrium, each force is proportional to the sine of the angle between the other two
B.a system in equilibrium does zero net work under any small imaginary displacement compatible with its constraints, giving reactions and member forces without solving equilibrium equations
C.distance from an axis at which the whole area could be concentrated to give the same moment of inertia, equal to the square root of I over A
D.sketch of a body isolated from its surroundings showing every external force, reaction and moment acting on it before equilibrium equations are written
8. Which term means: "sketch of a body isolated from its surroundings showing every external force, reaction and moment acting on it before equilibrium equations are written"?
A.Free body diagram — a system in equilibrium does zero net work under any small imaginary displacement compatible with its constraints, giving reactions and member forces without solving equilibrium equations
B.Free body diagram — sketch of a body isolated from its surroundings showing every external force, reaction and moment acting on it before equilibrium equations are written
C.Free body diagram — moment of a resultant about any point equals the algebraic sum of the moments of its component forces about that same point
D.Free body diagram — when three concurrent coplanar forces keep a body in equilibrium, each force is proportional to the sine of the angle between the other two
A.ratio of limiting friction to normal reaction between two dry surfaces, independent of the apparent contact area
B.when three concurrent coplanar forces keep a body in equilibrium, each force is proportional to the sine of the angle between the other two
C.distance from an axis at which the whole area could be concentrated to give the same moment of inertia, equal to the square root of I over A
D.a system in equilibrium does zero net work under any small imaginary displacement compatible with its constraints, giving reactions and member forces without solving equilibrium equations
A.Coefficient of friction — moment of a resultant about any point equals the algebraic sum of the moments of its component forces about that same point
B.Coefficient of friction — ratio of limiting friction to normal reaction between two dry surfaces, independent of the apparent contact area
C.Coefficient of friction — steepest inclination of a plane on which a body stays at rest under gravity alone, numerically equal to the angle of friction
D.Coefficient of friction — sketch of a body isolated from its surroundings showing every external force, reaction and moment acting on it before equilibrium equations are written
A.when three concurrent coplanar forces keep a body in equilibrium, each force is proportional to the sine of the angle between the other two
B.sketch of a body isolated from its surroundings showing every external force, reaction and moment acting on it before equilibrium equations are written
C.a system in equilibrium does zero net work under any small imaginary displacement compatible with its constraints, giving reactions and member forces without solving equilibrium equations
D.steepest inclination of a plane on which a body stays at rest under gravity alone, numerically equal to the angle of friction
A.Angle of repose — distance from an axis at which the whole area could be concentrated to give the same moment of inertia, equal to the square root of I over A
B.Angle of repose — a dynamic problem is converted to an equivalent static one by adding an inertia force equal to mass times acceleration acting opposite to the acceleration
C.Angle of repose — steepest inclination of a plane on which a body stays at rest under gravity alone, numerically equal to the angle of friction
D.Angle of repose — a system in equilibrium does zero net work under any small imaginary displacement compatible with its constraints, giving reactions and member forces without solving equilibrium equations
A.sketch of a body isolated from its surroundings showing every external force, reaction and moment acting on it before equilibrium equations are written
B.distance from an axis at which the whole area could be concentrated to give the same moment of inertia, equal to the square root of I over A
C.a dynamic problem is converted to an equivalent static one by adding an inertia force equal to mass times acceleration acting opposite to the acceleration
D.moment of inertia about any axis equals that about the parallel centroidal axis plus area times the square of the distance between the axes
17. Which term means: "moment of inertia about any axis equals that about the parallel centroidal axis plus area times the square of the distance between the axes"?
A.Parallel axis theorem — sketch of a body isolated from its surroundings showing every external force, reaction and moment acting on it before equilibrium equations are written
B.Parallel axis theorem — a dynamic problem is converted to an equivalent static one by adding an inertia force equal to mass times acceleration acting opposite to the acceleration
C.Parallel axis theorem — moment of a resultant about any point equals the algebraic sum of the moments of its component forces about that same point
D.Parallel axis theorem — moment of inertia about any axis equals that about the parallel centroidal axis plus area times the square of the distance between the axes
A.steepest inclination of a plane on which a body stays at rest under gravity alone, numerically equal to the angle of friction
B.when three concurrent coplanar forces keep a body in equilibrium, each force is proportional to the sine of the angle between the other two
C.a system in equilibrium does zero net work under any small imaginary displacement compatible with its constraints, giving reactions and member forces without solving equilibrium equations
D.a dynamic problem is converted to an equivalent static one by adding an inertia force equal to mass times acceleration acting opposite to the acceleration
20. Which term means: "a dynamic problem is converted to an equivalent static one by adding an inertia force equal to mass times acceleration acting opposite to the acceleration"?
A.D'Alembert's principle — a dynamic problem is converted to an equivalent static one by adding an inertia force equal to mass times acceleration acting opposite to the acceleration
B.D'Alembert's principle — sketch of a body isolated from its surroundings showing every external force, reaction and moment acting on it before equilibrium equations are written
C.D'Alembert's principle — distance from an axis at which the whole area could be concentrated to give the same moment of inertia, equal to the square root of I over A
D.D'Alembert's principle — when three concurrent coplanar forces keep a body in equilibrium, each force is proportional to the sine of the angle between the other two
A.ratio of limiting friction to normal reaction between two dry surfaces, independent of the apparent contact area
B.moment of a resultant about any point equals the algebraic sum of the moments of its component forces about that same point
C.when three concurrent coplanar forces keep a body in equilibrium, each force is proportional to the sine of the angle between the other two
D.a system in equilibrium does zero net work under any small imaginary displacement compatible with its constraints, giving reactions and member forces without solving equilibrium equations
23. Which term means: "a system in equilibrium does zero net work under any small imaginary displacement compatible with its constraints, giving reactions and member forces without solving equilibrium equations"?
A.Principle of virtual work — steepest inclination of a plane on which a body stays at rest under gravity alone, numerically equal to the angle of friction
B.Principle of virtual work — when three concurrent coplanar forces keep a body in equilibrium, each force is proportional to the sine of the angle between the other two
C.Principle of virtual work — a system in equilibrium does zero net work under any small imaginary displacement compatible with its constraints, giving reactions and member forces without solving equilibrium equations
D.Principle of virtual work — moment of inertia about any axis equals that about the parallel centroidal axis plus area times the square of the distance between the axes
A.sketch of a body isolated from its surroundings showing every external force, reaction and moment acting on it before equilibrium equations are written
B.when three concurrent coplanar forces keep a body in equilibrium, each force is proportional to the sine of the angle between the other two
C.distance from an axis at which the whole area could be concentrated to give the same moment of inertia, equal to the square root of I over A
D.moment of inertia about any axis equals that about the parallel centroidal axis plus area times the square of the distance between the axes
26. Which term means: "distance from an axis at which the whole area could be concentrated to give the same moment of inertia, equal to the square root of I over A"?
A.Radius of gyration — a system in equilibrium does zero net work under any small imaginary displacement compatible with its constraints, giving reactions and member forces without solving equilibrium equations
B.Radius of gyration — moment of inertia about any axis equals that about the parallel centroidal axis plus area times the square of the distance between the axes
C.Radius of gyration — distance from an axis at which the whole area could be concentrated to give the same moment of inertia, equal to the square root of I over A
D.Radius of gyration — steepest inclination of a plane on which a body stays at rest under gravity alone, numerically equal to the angle of friction
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