Engineering Mechanics MCQ Questions & Answers

81

A pair of smith's tongs is an example of the lever of

A) Zeroth order B) First order C) Second order D) Third order

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Answer & Solution

Answer: Option B

Solution:

First Order Levers: First class levers have the fulcrum between the force and the load. In using a screwdriver to lift the lid from a paint tin you are moving the effort over a greater distance than the load.

Second Order Levers: In second class levers the load is between the effort (force) and the fulcrum. A common example is a wheelbarrow where the effort moves a large distance to lift a heavy load, with the axle and wheel as the fulcrum.

Third-order levers: With third class levers the effort is between the load and the fulcrum, for example in barbecue tongs.

Source : primaryconnections.org.au

82

The centre of gravity of an isosceles triangle with base (p) and sides (q) from its base is

A) $$\frac{{\sqrt {4{{\text{p}}^2} - {{\text{q}}^2}} }}{6}$$ B) $$\frac{{4{{\text{p}}^2} - {{\text{q}}^2}}}{6}$$ C) $$\frac{{{{\text{p}}^2} - {{\text{q}}^2}}}{4}$$ D) $$\frac{{{{\text{p}}^2} + {{\text{q}}^2}}}{4}$$

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Answer & Solution

Answer: Option A

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83

The point, through which the whole weight of the body acts, irrespective of its position, is known as

A) Moment of inertia B) Center of gravity C) Center of percussion D) Center of mass

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Answer & Solution

Answer: Option B

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84

The resultant of the two forces ‘P’ and ‘Q’ is ‘R’. If ‘Q’ is doubled, the new resultant is perpendicular to ‘P’. Then

A) P = Q B) Q = R C) Q = 2R D) None of these

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Answer & Solution

Answer: Option B

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85

The moment of the force ‘P’ about ‘O’ as shown in the below figure is
Engineering Mechanics mcq question image

A) P × OA B) P × OB C) P × OC D) P × AC

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Answer & Solution

Answer: Option C

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86

The total momentum of a system of masses (i. e. moving bodies) in any one direction remains constant, unless acted upon by an external force in that direction. This statement is called

A) Newton's first law of motion B) Newton's second law of motion C) Principle of conservation of energy D) Principle of conservation of momentum

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Answer & Solution

Answer: Option D

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87

The unit of force in S.I. system of units is

A) Dyne B) Kilogram C) Newton D) Watt

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Answer & Solution

Answer: Option C

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88

The Cartesian equation of trajectory is (where u = Velocity of projection, $$\alpha $$ = Angle of projection and x, y = Co-ordinates of any point on the trajectory after t seconds.)

A) $${\text{y}} = \frac{{{\text{g}}{{\text{x}}^2}}}{{2{{\text{u}}^2}{{\cos }^2}\alpha }} + {\text{x}}\tan \alpha $$ B) $${\text{y}} = \frac{{{\text{g}}{{\text{x}}^2}}}{{2{{\text{u}}^2}{{\cos }^2}\alpha }} - {\text{x}}\tan \alpha $$ C) $${\text{y}} = {\text{x}}\tan \alpha - \frac{{{\text{g}}{{\text{x}}^2}}}{{2{{\text{u}}^2}{{\cos }^2}\alpha }}$$ D) $${\text{y}} = {\text{x}}\tan \alpha + \frac{{{\text{g}}{{\text{x}}^2}}}{{2{{\text{u}}^2}{{\cos }^2}\alpha }}$$

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Answer & Solution

Answer: Option C

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89

The velocity ratio of a first system of pulleys with 4 pulleys is

A) 4 B) 8 C) 16 D) 20

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Answer & Solution

Answer: Option C

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90

A body moves, from rest with a constant acceleration of 5 m per sec. The distance covered in 5 sec is most nearly

A) 38 m B) 62.5 m C) 96 m D) 124 m

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Answer & Solution

Answer: Option C

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Engineering Mechanics MCQ Questions & Answers | Mechanical Engineering