50 MCQs on Engineering Mechanics
Laws of Motion (12 MCQs)
-
Newton’s First Law is also known as:
a) Law of force
b) Law of acceleration
c) Law of inertia
d) Law of momentum
Ans: c -
The unit of force in SI system is:
a) Dyne
b) Pound
c) Newton
d) Joule
Ans: c -
According to Newton’s Second Law, force is equal to:
a) mv
b) ma
c) m/g
d) m/a
Ans: b -
A force of 10 N acts on a body of mass 2 kg. Acceleration is:
a) 0.2 m/s²
b) 5 m/s²
c) 20 m/s²
d) 10 m/s²
Ans: b -
Impulse is defined as:
a) Rate of change of momentum
b) Force × Distance
c) Force × Time
d) Mass × Acceleration
Ans: c -
Momentum is:
a) mv²
b) mv
c) ma
d) m/v
Ans: b -
The law of conservation of momentum is valid when:
a) No external force acts
b) Only gravitational force acts
c) Acceleration is zero
d) Speed is uniform
Ans: a -
The relationship between impulse and momentum is given by:
a) I = mv²
b) I = mgh
c) I = Δ(mv)
d) I = ½mv²
Ans: c -
A body continues in its state of rest or motion unless:
a) It is in vacuum
b) External force acts on it
c) Gravity is zero
d) Mass is negligible
Ans: b -
Force is a:
a) Scalar quantity
b) Pseudo vector
c) Vector quantity
d) None
Ans: c -
Newton’s third law implies:
a) F = ma
b) Action = Reaction
c) Every force has inertia
d) None
Ans: b -
Unit of impulse is:
a) kg m²/s
b) N/s
c) N·s
d) kg/s
Ans: c
🔹 Moment and Force Systems (10 MCQs)
-
Moment of a force is:
a) Force × Distance
b) Mass × Distance
c) Force / Area
d) Force × Time
Ans: a -
Unit of moment in SI system is:
a) N·s
b) N·m
c) J
d) kg·m
Ans: b -
A couple produces:
a) Translational motion
b) Rotational motion
c) Both
d) None
Ans: b -
The resultant of two equal forces at 90° is:
a) √2F
b) 2F
c) F
d) 0
Ans: a -
The direction of moment is given by:
a) Right-hand rule
b) Newton’s law
c) Hooke’s law
d) Coulomb’s law
Ans: a -
A force is completely defined when:
a) Its magnitude is given
b) Direction is given
c) Line of action is given
d) All of the above
Ans: d -
A force that does not produce moment about its own line of action is called:
a) Torque
b) Axial force
c) Sliding force
d) Coplanar force
Ans: b -
The algebraic sum of moments of a system about any point is equal to moment of:
a) Net force
b) Resultant force
c) Reaction force
d) Zero
Ans: b -
The principle of moments is also known as:
a) Lami’s theorem
b) Varignon’s theorem
c) Newton’s law
d) Pascal’s principle
Ans: b -
In 2D force system, number of components for a single force:
a) 1
b) 2
c) 3
d) 4
Ans: b
🔹 Equilibrium (10 MCQs)
-
A body is in equilibrium when:
a) ΣF = 0 only
b) ΣM = 0 only
c) ΣF = 0 and ΣM = 0
d) Force acts at center
Ans: c -
Lami’s Theorem applies to:
a) Two force system
b) Three non-concurrent forces
c) Three concurrent, coplanar forces
d) Four forces
Ans: c -
A body is subjected to two equal and opposite forces. It will:
a) Rotate
b) Translate
c) Stay in equilibrium
d) Accelerate
Ans: c -
A body remains in static equilibrium if:
a) Net force is zero
b) Net moment is zero
c) Both a and b
d) Only one force acts
Ans: c -
In 3D system, equilibrium requires:
a) 3 conditions
b) 2 conditions
c) 6 conditions
d) 1 condition
Ans: c -
For equilibrium of a particle in plane:
a) ΣFx = 0, ΣFy = 0
b) ΣFz = 0
c) ΣM = 0
d) Σa = 0
Ans: a -
Equilibrant force is:
a) Equal to resultant
b) Opposite to resultant
c) Perpendicular to resultant
d) None
Ans: b -
Condition for equilibrium in coplanar concurrent forces:
a) ΣFx = 0
b) ΣFy = 0
c) Both a and b
d) ΣM = 0 only
Ans: c -
Reaction at smooth surface is:
a) Tangential
b) Normal
c) Inclined
d) Zero
Ans: b -
Frictional force always acts:
a) Along motion
b) Opposite to motion
c) At 45°
d) Vertically
Ans: b
🔹 Centroid and Moment of Inertia (18 MCQs)
-
Centroid is:
a) Center of gravity
b) Center of area
c) Center of volume
d) Center of mass
Ans: b -
Centroid of a semicircle lies at:
a) Center
b) 2R/3 from base
c) 4R/3π from base
d) R/2 from base
Ans: c -
Centroid of triangle is at intersection of:
a) Bisectors
b) Altitudes
c) Medians
d) Perpendicular bisectors
Ans: c -
Moment of inertia depends on:
a) Mass
b) Area
c) Distance from axis
d) All of these
Ans: d -
Unit of area moment of inertia is:
a) m⁴
b) m²
c) m
d) m³
Ans: a -
Parallel axis theorem relates moment of inertia about:
a) Any axis to centroidal axis
b) Same axis
c) Perpendicular axis
d) Horizontal axis only
Ans: a -
Perpendicular axis theorem is valid for:
a) 3D bodies
b) Hollow sphere
c) Plane lamina
d) Rods
Ans: c -
M.I. of a thin rectangular section about base is:
a) bh³/12
b) bh³/3
c) bh³/36
d) hb³/12
Ans: b -
M.I. of a circular section about its centroid is:
a) πd⁴/64
b) πd⁴/32
c) πd⁴/16
d) πd⁴/8
Ans: a -
The radius of gyration is given by:
a) I = kA
b) k = √(I/A)
c) I = k²A
d) Both b and c
Ans: d -
The centroid of a uniform semicircular lamina is located:
a) At center
b) 0.424R from flat face
c) R/2 from base
d) At curved edge
Ans: b -
The centroid of a full circle is:
a) At center
b) At edge
c) At any diameter
d) Undefined
Ans: a -
For composite areas, centroid is found using:
a) Simple mean
b) Weighted average
c) Arithmetic mean
d) Geometric mean
Ans: b -
Moment of inertia is additive for:
a) Parallel bodies
b) Composite bodies
c) Point masses only
d) None
Ans: b -
Moment of inertia of thin rod about its center is:
a) ml²
b) ml²/12
c) ml²/3
d) ml/2
Ans: b -
Centroid and center of gravity coincide when:
a) Mass is uniform
b) Object is small
c) Object is symmetrical
d) Both a and c
Ans: d -
Centroid is denoted by:
a) G
b) C
c) Z
d) O
Ans: b -
Moment of inertia of rectangle about centroidal horizontal axis:
a) bh³/12
b) bh²/2
c) hb³/12
d) hb²/2
Ans: a