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# Engineering Mechanics MCQ ### 1.The coefficient of friction depends upon

• ANature of surfaces
• BArea of contact
• CShape of the surfaces
• DAll of the above
Correct Answer : (A)

Nature of surfaces

Explanation:

### 2.The energy possessed by a body, for doing work by virtue of its position, is called

• APotential energy
• BKinetic energy
• CElectrical energy
• DChemical energy
Correct Answer : (A)

Potential energy

Explanation:

### 3.The friction experienced by a body, when at rest, is known as

• AStatic friction
• BDynamic friction
• CLimiting friction
• DCoefficient of friction
Correct Answer : (A)

Static friction

Explanation:

### 4.For any system of coplanar forces, the condition of equilibrium is that the

• AAlgebraic sum of the horizontal components of all the forces should be zero
• BAlgebraic sum of the vertical components of all the forces should be zero
• CAlgebraic sum of moments of all the forces about any point should be zero
• DAll of the above
Correct Answer : (D)

All of the above

Explanation:

### 5.According to parallel axis theorem, the moment of inertia of a section about an axis parallel to the axis through center of gravity (i.e. IP) is given by(where, A = Area of the section, IG = Moment of inertia of the section about an axis passing through its C.G., and h = Distance between C.G. and the parallel axis.)

• AIP = IG + Ah2
• BIP = IG - Ah2
• CIP = IG / Ah2
• DIP = Ah2 / IG
Correct Answer : (A)

IP = IG + Ah2

Explanation:

### 6.The efficiency of a lifting machine is the ratio of

• AOutput to the input
• BWork done by the machine to the work done on the machine
• CMechanical advantage to the velocity ratio
• DAll of the above
Correct Answer : (D)

All of the above

Explanation:

### 7.The mechanical advantage of a lifting machine is the ratio of

• ADistance moved by effort to the distance moved by load
• BLoad lifted to the effort applied
• COutput to the input
• DAll of the above
Correct Answer : (B)

Load lifted to the effort applied

Explanation:

### 8.The angle between two forces when the resultant is maximum and minimum respectively are

• A0° and 180°
• B180° and 0°
• C90° and 180°
• D90° and 0°
Correct Answer : (A)

0° and 180°

Explanation:

### 9.The skidding away of the vehicle on a level circular path can be avoided if the force of friction between the wheels and the ground is __________ the centrifugal force.

• ALess than
• BGreater than
• CEqual to
• DNone of these
Correct Answer : (B)

Greater than

Explanation:

### 10.Moment of inertia of a circular section about an axis perpendicular to the section is

• Aπd3/16
• Bπd3/32
• Cπd4/32
• Dπd4/64
Correct Answer : (C)

πd4/32

Explanation:

### 11.The linear acceleration (a) of a body rotating along a circular path of radius (r) with an angular acceleration of α rad/s2, is

• Aa = α/ r
• Ba = α.r
• Ca = r / α
• DNone of these
Correct Answer : (B)

a = α.r

Explanation:

### 12.If a number of forces are acting at a point, their resultant is given by

• A(∑V)2 + (∑H)2
• B√[(∑V)2 + (∑H)2]
• C(∑V)2 +(∑H)2 +2(∑V)(∑H)
• D√[(∑V)2 +(∑H)2 +2(∑V)(∑H)]
Correct Answer : (B)

√[(∑V)2 + (∑H)2]

Explanation:

### 13.A framed structure is perfect, if the number of members are __________ (2j - 3), where j is the number of joints.

• AEqual to
• BLess than
• CGreater than
• DNone of these
Correct Answer : (A)

Equal to

Explanation:

### 14.The resultant of two equal forces ‘P’ making an angle ‘θ’, is given by

• A2P sinθ/2
• B2P cosθ/2
• C2P tanθ/2
• D2P cotθ/2
Correct Answer : (B)

2P cosθ/2

Explanation:

### 15.The maximum height of a projectile on a horizontal plane, is

• Au² sin²α/2g
• Bu² cos²α/2g
• Cu² sin²α/g
• Du² cos²α/g
Correct Answer : (A)

u² sin²α/2g

Explanation:

### 16.If a given force (or a given system of forces) acting on a body __________ the position of the body, but keeps it in equilibrium, then its effect is to produce internal stress in the body.

• AChange
• BDoes not change
• CChanges periodically
• DNone of these
Correct Answer : (B)

Does not change

Explanation:

### 17.The velocity of a particle (v) moving with simple harmonic motion, at any instant is given by (where, r = Amplitude of motion, and y = Displacement of the particle from mean position.)

• Aω.√(y² - r²)
• Bω.√(r² - y²)
• Cω².√(y² - r²)
• Dω².√(r² - y²)
Correct Answer : (B)

ω.√(r² - y²)

Explanation:

### 18.The frequency of oscillation of a compound pendulum is (where kG = Radius of gyration about the centroidal axis, and h = Distance between the point of suspension and C.G. of the body.)

• A2π. √(gh/kG² + h²)
• B2π. √(kG² + h²/gh)
• C1/2π. √(gh/kG² + h²)
• D1/2π. √(kG² + h²/gh)
Correct Answer : (C)

1/2π. √(gh/kG² + h²)

Explanation:

### 19.When the spring of a watch is wound, it will possess

• AStrain energy
• BKinetic energy
• CHeat energy
• DElectrical energy
Correct Answer : (A)

Strain energy

Explanation:

### 20.The potential energy of a vertically raised body is __________ the kinetic energy of a vertically falling body.

• AEqual to
• BLess than
• CGreater than
• DNone of these
Correct Answer : (A)

Equal to

Explanation: