Civil Engineering - Applied Mechanics MCQs Part 2

1. The following factor affects the orbit of a satellite up to an altitude of 720 km from the earth's surface

A.
uneven distribution of the gravitational field

B.
gravity of the sun and the moon

C.
aerodynamic forces

D.
none of these.

 Answer Option D

2. If α and u are the angle of projection and initial velocity of a projectile respectively, the horizontal range of the projectile, is

A.

B.

C.

D.

 Answer Option A

3. Newton's law of Collision of elastic bodies states that when two moving bodies collide each other, their velocity of separation

A.
is directly proportional to their velocity of approach

B.
is inversely proportional to their velocity of approach

C.
bears a constant ratio to their velocity of approach

D.
is equal to the sum of their velocities of approach.

 Answer Option C

4. Two forces of 6 Newtons and 8 Newtons which are acting at right angles to each other, will have a resultant of

A.
5 Newtons

B.
8 Newtons

C.
10 Newtons

D.
12 Newtons.

 Answer Option C

5. A projectile is fired with a velocity of 100.3 m/sec. at an elevation of 60°. The velocity attained by the projectile when it is moving at a height of 100 m, is

A.
70 m/sec.

B.
75 m/sec.

C.
80 m/sec.

D.
85 m/sec.

E.
90 m/sec.

 Answer Option E

6. A body is said to move with Simple Harmonic Motion if its acceleration, is

A. always directed away from the centre, the point of reference

B. proportional to the square of the distance from the point of reference

C. proportional to the distance from the point of reference and directed towards it

D. inversely proportion to the distance from the point of reference

E. none of these.

 Answer Option C

7. One end of a light string 4 m in length is fixed to a point on a smooth wall and the other end fastened to a point on the surface of a smooth sphere of diameter 2.25 m and of weight 100 kg. The reaction between the sphere and the wall of the arrangement made is

A. 102.5 kg

B. 105.5 kg

C. 108.5 kg

D. 110 kg.

 Answer Option A

8. Which one of the following laws is not applicable to a simple pendulum ?.

A. The time period does not depend on its magnitude

B. The time period is proportional to its length l

C. The time period is proportional to l where l is length

D. The time period is inversely proportional to g where g is the acceleration due to gravity.

 Answer Option B

9. The ratio of the reactions RA and RB of a simply supported beam shown in below figure is

A. 0.50

B. 0.40

C. 0.67

D. 1.00

E. 1.50

 Answer Option D

10. Effect of a force on a body depends upon its

A. direction

B. magnitude

C. position

D. all the above.

 Answer Option D

11. The resultant of the forces acting on a body will be zero if the body

A. rotates

B. moves with variable velocity in a straight line

C. moves along a curved path

D. does not move at all.

 Answer Option D

12. A ball moving with a velocity of 5 m/sec impinges a fixed plane at an angle of 45° and its direction after impact is equally inclined to the line of impact. If the coefficient of restitution is 0.5, the velocity of the ball after impact will be

A. 0.5 m/sec

B. 1.5 m/sec

C. 2.5 m/sec

D. 3.5 m/sec

E. 4.5 m/sec.

 Answer Option C

13. A pilot flies a small plane in a vertical loop of radius r. At the top of its trajectory he experiences weightlessness. If the acceleration due to gravity is g, the speed of the plane at the top of its trajectory would be

A. zero

B. infinite

C. gr

D. 2gr.

 Answer Option C

14. The distance of the c.g. of a semi-circular arc of radius r from its diameter along the radius of symmetry, is

A.

B.

C.

D.

 Answer Option D

15. A Seconds pendulum executes

A. 0.5 beat per second

B. 1.0 beat per second

C. 2.0 beats per second

D. 2.5 beats per second

E. 3 beats per second.

 Answer Option C

16. The ratio of the ranges on the inclined plane with motion upward and with motion downward for a given velocity, angle of projection will be

A.

B.

C.

D.

 Answer Option B

17. For maximum range of a projectile, the angle of projection should be

A. 30°

B. 45°

C. 60°

D. none of these.

 Answer Option B

18. M.I. of a thin ring (external diameter D, internal diameter d) about an axis perpendicular to the plane of the ring, is

A. (D4 + d4)

B. (D4 - d4)

C. (D4 + d4)

D. (D4 x d4).

 Answer Option B

19. Pick up the correct statement from the following for the structure shown in below figure.

A. The horizontal reaction at A is 23t ←

B. The horizontal reaction at C is 23t →

C. The vertical reaction at A is zero

D. The vertical reaction at C is 2 t ↑

E. All the above.

 Answer Option E

20. A particle moves with a velocity of 2 m/sec in a straight line with a negative acceleration of 0.1 m/sec2. Time required to traverse a distance of 1.5 m, is

A. 40 sec

B. 30 sec

C. 20 sec

D. 15 sec

E. 10 sec.

 Answer Option C

21. When a body of mass M1 is hanging freely and an other of mass M2 lying on a smooth inclined plane(α) are connected by a light indextensible string passing over a smooth pulley, the acceleration of the body of mass M1, will be given by

A.

B.

C.

D.

 Answer Option B

22. According to Law of Triangle of Forces

A. three forces acting at a point, can be rep-resented by the sides of a triangle, each side being in proportion to the force

B. three forces acting along the sides of a triangle are always in equilibrium

C. if three forces acting on a, point can be represented.in magnitude and direction, by the sides of a triangle taken in order, these will be in equilibrium

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. if the forces acting on a particle be represented in magnitude and direction by the two sides of a triangle taken in order, their resultant will be represented in magnitude and direction by the third side of the triangle, taken in opposite order.

 Answer Option E

23. A Second's pendulum gains 2 minutes a day. To make it to keep correct time its length

A. must be decreased

B. must be increased

C. is not changed but weight of the bob is increased

D. is not changed but weight of the bob is decreased

E. none of these.

 Answer Option B

24. The following is not a law of static friction :

A. The force of friction always acts in a direction opposite to that in which the body tends to move

B. The force of friction is dependent upon the area of contact

C. The force of friction depends upon the roughness of the surface

D. The magnitude of the limiting friction bears a constant ratio to the normal reaction between two surfaces.

 Answer Option A

25. The velocity of a moving body, is

A. a vector quantity

B. a scalar quantity

C. a scalar as well as a vector quantity

D. none of these.

 Answer Option A

26. A spring scale in a stationary lift shows a reading of 60 kg for a man standing on it. If the lift starts descending at an acceleration of g/5, the scale reading would be

A. 48 kg

B. 60 kg

C. 72 kg

D. none of these.

 Answer Option A

27. The resolved part of the resultant of two forces inclined at an angle θ in a given direction is

A. algebraic sum of the resolved parts of the forces in the direction

B. arithmetical sum of the resolved parts of the forces in the direction

C. difference of the forces multiplied by cosine θ°

D. sum of the forces multiplied by the sine θ

E. sum of the forces multiplied by the tangent θ°.

 Answer Option A

28. The velocity ratio of the differential wheel and axle is

A.

B.

C.

D.

 Answer Option B

29. The following statement is one of the laws of Dynamic friction

A. The force of friction always acts in a direction opposite to that in which a body is moving

B. The magnitude of the kinetic friction bears a constant ratio to the normal reaction between two surfaces. The ratio being slightly less than that in the case of limiting friction

C. For moderate speeds the force of friction remains constant but decreases slightly with the increase of speed

D. all the above.

 Answer Option D

30. A 50 kg boy climbs up a 8 m rope in gymnasiam in 10 sec. The average power developed by the boy is approximately

A. 400 watts

B. 500 watts

C. 4000 watts

D. none of these.

 Answer Option A

31. Lami's theroem states that

A. three forces acting at a point are always in equilibrium

B. if three forces acting on a point can be represented in magnitude and direction by the sides of a triangle, the point will be in the state of equilibrium

C. three coplaner forces acting at a point will be in equilibrium, if each force is proportional to the sine of the angle between the other two

D. three coplaner forces acting at a point will be in equilibrium if each force is inversely proportional to the sine of the angle between the other two

E. none of these.

 Answer Option C

32. Pick up the incorrect statement from the following. In case of suspension bridge due to rise in temperature,

A. dip of the cable increases

B. length of the cable increases

C. dip of the cable decreases

D. none of the these.

 Answer Option C

33. If two forces acting at a point are in equilibrium, they must be equal in magnitude and their line of action must be along

A. the same line in the same sense

B. the same line in opposite sense

C. the perpendicular to both the lines

D. none of these.

 Answer Option B

34. For lifting a load of 50 kg through a distance of 2.5 cm, an effort of 12.5 kg is moved through a distance of 40 cm. The efficiency of the lifting machine, is

A. 60%

B. 65%

C. 70%

D. 25%.

 Answer Option D

35. Power can be expressed as

A. work/energy

B. work/time

C. work x time

D. work/distance.

 Answer Option B

36. The ends of a string weighing w/metre are attached to two points at the same horizontal level. If the central dip is very small, the horizontal tension of the string throughout is

A.

B.

C.

D.

 Answer Option C

37. If two forces P and Q (P > Q) act on the same straight line but in opposite direction, their resultant, is

A. P + Q

B. P/Q

C. Q/P

D. P - Q

E. Q - P.

 Answer Option D

38. If the angle between the applied force and the direction of motion of a body, is between 90° and 180°, the work done, is called

A. virtual work

B. imaginary work

C. zero work

D. negative work.

 Answer Option D

39. The units of moment of inertia of an area, are

A. kg/m

B. kg/m2

C. m4

D. m3

E. kg-m2.

 Answer Option C

40. To avoid bending action at the base of a pier,

A. suspension and anchor cables are kept at the same level

B. suspension and anchor cables are fixed to pier top

C. suspension cable and anchor cables are attached to a saddle mounted on rollers on top of the pier

D. none the these.

 Answer Option B

41. For a body moving with simple harmonic motion, the number of cycles per second, is known as its

A. oscillation

B. amplitude

C. periodic time

D. beat

E. frequency.

 Answer Option E

42. If the horizontal range is 2.5 times the greatest height, the angle of projection of the projectile, is

A. 57°

B. 58°

C. 59°

D. 60°.

 Answer Option B

43. The shape of a suspended cable under its own weight, is

A. parabolic

B. circular

C. catenary

D. elliptical.

 Answer Option C

44. Time required to stop a car moving with a velocity 20 m/sec within a distance of 40 m, is

A. 2 sec

B. 3 sec

C. 4 sec

D. 5 sec

E. 6 sec.

 Answer Option C

45. The characteristic of a couple, is :

A. algebraic sum of forces, constituting a couple is zero

B. algebraic sum of moments of forces, constituting a couple, about any poin, is same

C. a couple can be balanced only by a couple but of opposite sense

D. a couple can be never the balanced by a single force

E. all the above.

 Answer Option E

46. Ball A of mass 250 g moving on a smooth horizontal table with a velocity of 10 m/s hits an identical stationary ball B on the table. If the impact is perfectly elastic, the velocity of the ball B just after impact would be

A. zero

B. 5 m/sec

C. 10 m/sec

D. none of these.

 Answer Option C

47. Equation of motion of a point in a straight line, is

A. v = u + ft

B. S = ut + ft2

C. 2fS = v2 - u2

D. all the above.

 Answer Option D

48. For the system of the loads shown in below figure, the time required for the 6.6 kg load to fall on the edge, is

A. 1 sec.

B. 2 sec.

C. 3 sec.

D. 4 sec.

E. 5 sec.

 Answer Option C

49. One end of a light string 4 m in length is fixed to a point on a smooth wall and the other end fastened to a point on the surface of a smooth sphere of diameter 2.25 m and of weight 100 kg. The tension in the string is

A. 17.5 kg

B. 19.5 kg

C. 22.5 kg

D. 25 kg.

 Answer Option C

50. The inherent property of a body which offers reluctance to change its state of rest or uniform motion, is

A. weight

B. mass

C. interia

D. momentum.

 Answer Option C