mechanical engineering MCQs – Page 179

Practise multiple-choice questions from mechanical engineering for competitive examinations and subject revision. Review each marked answer and report any item that may be outdated or unclear.

3561. The center of percussion of the homogeneous rod of length L suspended at the top will be___________________?
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A. 3L/8

B. 2L/3

C. 3L/4

D. L/2

E. L/3

3562. The maximum frictional force which comes into play when a body just begins to slide over another surface is called__________________?
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A. sliding friction

B. kinematic friction

C. limiting friction

D. dynamic friction

E. rolling friction

3563. Center of percussion is___________________?
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A. point of suspension

B. the point of application of the resultant of all the forces tending to cause a body to rotate about a certain axis

C. the point of C.G.

D. the point in a body about which it can rotate horizontally and oscillate under the influence of gravity

E. the point of metacentre

3564. Effect of a force on a body depends upon ________________?
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A. none of the above

B. direction

C. magnitude

D. all of the above

E. position or line of action

3565. If a number of forces act simultaneously on a particle, it is possible _____________________?
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A. to replace them by a single force

B. not a replace them by a single force

C. to replace them by a single force through C.G.

D. to replace them by a couple

E. to replace them by a couple and a force

3566. A cable with a uniformly distributed load per horizontal meter run will take the following shape________________?
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A. part of a circle

B. elliptical

C. hyperbola

D. straight line

E. parabola
3567. If two equal forces of magnitude P act at an angle 9, their resultant will be________________?
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A. P/2 cos 9/2

B. IP cos 9/2

C. Psin 9/2

D. 2P tan 9/2

E. IP sin 9/2

3568. Two non-collinear parallel equal forces acting in opposite direction__________________?
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A. constitute a moment of couple

B. balance each other

C. constitute a couple

D. constitute a resultant couple

E. constitute a moment

3569. The units of moment of inertia of mass are ________________?
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A. kg m2

B. m4

C. kg/m2

D. kg/m

E. m2/kg

3570. A heavy ladder resting on floor and against a vertical wall may not be in equilibrium, if____________________?
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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

E. will be in equilibrium under all conditions

3571. According to law of triangle of forces __________________ ?
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A. three forces acting at a point will be in equilibrium

B. if three forces acting upon a patticle are represented in magnitude and direction by the sides of a triangle, taken in order, they will be in equilibrium

C. none of the above

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

E. three forces acting at a point can be represented by a triangle, each side being proportional to force

3572. When trying to turn a key into a lock, following is applied _____________________?
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A. moment

B. coplanar force

C. couple

D. non-coplanar forces

E. lever

3573. The algebraic sum of moments of the forces forming couple about any point in their plane is_________________?
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A. equal to the moment of the couple

B. constant

C. both of above are correct

D. both of above are wrong

E. none of the above

3574. The C.G. of a solid hemisphere lies on the central radius 3r________________?
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A. at distance from the plane base or

B. at distance from the plane base 3r

C. at distance from the plane base 3r

D. at distance from the plane base

E. at distance from the plane base 3r

3575. Center of gravity of a solid cone lies on the axis at the height _____________________?
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A. one-third of the total height above base

B. one-half of the total height above base

C. none of the above

D. one-fourth of the total height above base

E. three-eighth of the total height above the base

3576. If rain is falling in the opposite direction of the movement of a pedestrain, he has to hold his umbrella___________________?
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A. none of the above

B. more inclined when moving

C. less inclined when standing

D. more inclined when standing

E. less inclined when moving

3577. Dynamic friction as compared to static friction is___________________?
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A. less

B. more

C. may be less of more depending on nature of surfaces and velocity

D. has no correlation

E. same

3578. Which of the following is not a vector quantity __________________?
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A. velocity

B. acceleration

C. weight

D. force

E. moment

3579. Which is the correct statement about law of polygon of forces ?
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A. if any number of forces acting at a point can be represented in direction and magnitude by the sides of a polygon, then the forces are in equilibrium

B. a polygon taken in order, then the forces are in equilibrium

C. if a polygon representing forces acting at a point is closed then forces are in equilibrium

D. if any number of forces acting at a point can be represented by the sides

E. if any number of forces acting at a point can be represented in direction and magnitude by the sides of a polygon taken in order, then the forces are in equilibrium

F. none of the above.

3580. The forces, which meet at one point, but their lines of action do not lie in a plane, are called_________________?
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A. coplanar non-concurrent forces

B. non-coplanar non-concurrent forces

C. intersecting forces

D. none of the above

E. non-coplanar concurrent forces