# Engineering Mechanics Multiple Choice Questions(MCQs) & Answers

Engineering Mechanics Multiple Choice Questions(MCQs)& Answers Engineering Mechanics

# CONCEPTS & THEORIES

engineering-mechanics

Engineering mechanics is the application of mechanics to solve problems involving common engineering elements. The goal of Engineering Mechanics course is to expose students to problems in mechanics as applied to plausibly real-world scenarios. Problems of particular types are explored in detail in the hopes that students will gain an inductive understanding of the underlying principles at work.

## Types of Engineering Mechanics:

Engineering mechanics can be classified into two types-
A. Statics: Statics is the branch of mechanics that deals with the study of objects at rest. Objects at rest may or may not be under the influence of forces.
B. Dynamics: Dynamics is the branch of mechanics that deals with the study of objects in motion and the forces causing such motion.
Dynamics can be further classified into two types-
1. Kinematics: Kinematics is the study of the motion of bodies without consideration of the cause of the motion. Kinematics deals with the space-time relationship of the motion of a body. Some examples of kinematic concepts are displacement, velocity and acceleration.
2. Kinetics: Kinetics is the branch of mechanics which deals with the study of the motion of bodies by considering the cause of motion.

## Some basic terms used in Mechanics

Mass: The quantity of the matter possessed by a body is called mass. The mass of a body can not change unless the body is damaged and part of it is physically separated.
Length: It is a concept to measure linear distances.
Time: Time is the measure of succession of events. The successive event selected is the rotation of earth about its own axis and this is called a day.
Space: Any geometric region in which the study of a body has been done is called space.
Displacement: It is defined as the distance moved by a body/particle in the specified direction.
Velocity: The rate of change of displacement with respect to time is defined as velocity.
Acceleration: It is the rate of change of velocity with respect to time.
Momentum: The product of mass and velocity is called momentum. Thus
Momentum = Mass × Velocity
Particle: It can be defined as an object which has only mass and no size.

# Engineering Multiple Choice Questions(MCQs)& Answers

1 three forces acting in one plane upon a rigid body, keep it in equilibrium, then they must either
A meet in a point
B be all parallel
C at least two of them must meet
D all the above are correct

Answer: all the above are correct
2 A single force and a couple acting in the same plane upon a rigid body
A balance each other
B cannot balance each other
C produce moment of a couple
D are equivalent

3 The maximum frictional force which comes into play when a body just begins to slide over another surface is called
A limiting friction
B dynamic friction
C sliding friction
D rolling friction

4 The co-efficient of friction depends upon
A nature of surfaces
B area of contact
C shape of the surfaces
D ail of the above.

5 The effort required to lift a load W on a screw jack with helix angle a and angle of friction <j) is equal to
A Wtan(a + )
B Wtan(a-)
C Wcos(a + )
D Wsin(a + )

6 Kinetic friction is the
A tangent of angle between normal reaction and the resultant of normal reaction and the limiting friction
B ratio of limiting friction and normal reaction
C the friction force acting when the body is just about to move
D the friction force acting when the body is in motion

Answer: the friction force acting when the body is in motion
7 Tangent of angle of friction is equal to
A kinetic friction
B limiting friction
C angle of repose
D coefficient of friction

8 Dynamic friction as compared to static friction is
A same
B more
C less
D may be less of more depending on nature of surfaces and velocity

9 Coulomb friction is the friction between
A bodies having relative motion
B two dry surfaces
C two lubricated surfaces
D solids and liquids

10 Limiting force of friction is the
A tangent of angle between normal-reaction and the resultant of normal reaction and limiting friction
B ratio of limiting friction and normal reaction
C the friction force acting when the body is just about to move
D the friction force acting when the body is in motion

Answer: the friction force acting when the body is just about to move
11 If rain is falling in the opposite direction of the movement of a pedestrain, he has to hold his umbrella
A more inclined when moving
B less inclined when moving
C more inclined when standing
D less inclined when standing

12 A particle moves along a straight line such that distance (x) traversed in t seconds is given by x = t2 (t – 4), the acceleration of the particle will be given by the equation
A 3t2-lt
B 3t2+2t
C 6f-8
D 6f-4

13 Pick up wrong statement about friction force for dry surfaces. Friction force is
A proportional to normal load between the surfaces
B dependent on the materials of contact surface
C proportional to velocity of sliding
D independent of the area of contact surfaces

Answer: proportional to velocity of sliding
14 Coefficient of friction is the
A angle between normal reaction and the resultant of normal reaction and the limiting friction
B ratio of limiting friction and normal reaction
C the friction force acting when the body is just about to move
D the friction force acting when the body is in motion

Answer: ratio of limiting friction and normal reaction
15 Frictional force encountered after commencement of motion is called
A post friction
B limiting friction
C kinematic friction
D dynamic friction

16 On the ladder resting on the ground and leaning against a smooth vertical wall, the force of friction will be
A downwards at its upper end
B upwards at its upper end
C perpendicular to the wall at its upper end
D zero at its upper end

17 On a ladder resting on smooth ground and leaning against vertical wall, the force of friction will be
A towards the wall at its upper end
B away from the wall at its upper end
C upwards at its upper end
D downwards at its upper end

Answer: upwards at its upper end
18 Which one of the following statements is not correct
A the tangent of the angle of friction is equal to coefficient of friction
B the angle of repose is equal to angle of friction
C the tangent of the angle of repose is equal to coefficient of friction
D the sine of the angle of repose is equal to coefficient to friction

Answer: the sine of the angle of repose is equal to coefficient to friction
19 The ratio of limiting friction and normal reaction is known as
A coefficient of friction
B angle of friction
C angle of repose
D sliding friction

20 Least force required to draw a body up the inclined plane is W sin (plane inclination + friction angle) applied in the direction
A along the plane
B horizontally
C vertically
D at an angle equal to the angle of friction to the inclined plane

Answer: at an angle equal to the angle of friction to the inclined plane
21 According to principle of transmissibility of forces, the effect of a force upon a body is
A maximum when it acts at the center of gravity of a body
B different at different points in its line of action
C the same at every point in its line of action
D minimum when it acts at the C.G. of the body

Answer: the same at every point in its line of action
22 Which of the following is not a scalar quantity
A time
B mass
C volume
D acceleration

23 When trying to turn a key into a lock, following is applied
A couple
B moment
C coplanar force
D non-coplanar forces

24 The forces, which meet at one point, but their lines of action do not lie in a plane, are called
A coplanar non-concurrent forces
B non-coplanar concurrent forces
C non-coplanar non-concurrent forces
D intersecting forces

25 The weight of a body is due to
A gravitational force of attraction towards the center of the earth
B force of attraction experienced by particles
C centripetal force of earth
D gravitational pull exerted by the earth

Answer: gravitational force of attraction towards the center of the earth
26 Which of the following is not the unit of pressure ?
A newton
B mm of wcl
C kg/cm
D ata

27 Which of the following is not the unit of work, energy and heat ?
A hp
B kWhr
C kcal
D kg m

28 Which of the following is not the unit of distance ?
A milestone.
B millimetre
C angstrom
D light year

29 Which of the following do not have identical dimensions ?
A Torque and work
B Moment of a force and angular momentum
C Momentum and impulse
D Torque and energy

Answer: Moment of a force and angular momentum.
30 The resolved part of the resultant of two forces inclined at an angle 9 in a given direction is equal to
A the algebraic sum of the resolved parts of the forces in the given direction
B the sum of the forces multiplied by the sine of 9
C the sum of the resolved parts of the forces in the given direction
D the sum of the forces multiplied by the tangent of 9.

Answer: the algebraic sum of the resolved parts of the forces in the given direction
31 The algebraic sum of the resolved parts of a number of forces in a given direction is equal to the resolved part of their resultant in the same direction. This is as per the principle of
A forces
B independence of forces
C resolution of forces
D dependence of forces

32 If two equal forces of magnitude P act at an angle 9°, their resultant will be
A IP cos 9/2
B 2P tan 9/2
C P/2 cos 9/2
D IP sin 9/2

33 A force is completely defined when we specify
A point of application
B direction
C magnitude
D all of the above

34 If a number of forces act simultaneously on a particle, it is possible
A not a replace them by a single force
B to replace them by a single force
C to replace them by a single force through C.G.
D to replace them by a couple

Answer: to replace them by a single force
35 Effect of a force on a body depends upon
A position or line of action
B direction
C magnitude
D all of the above

36 force acting on a body may
A retard its motion
B balance the other forces acting on it
C introduce internal stresses
D all of the above

37 Forces are called coplanar when all of them acting on body lie in
A one point
B one plane
C different planes
D perpendicular planes

38 Forces are called concurrent when their lines of action meet in
A one point
B perpendicular planes
C two points
D plane

39 The unit of force in S.I. units is
A kilogram
B newton
C watt
D dyne

40 The unit of power in S.I. units is
A newton meter
B watt
C joule
D kilogram meter/sec.

41 three forces acting in one plane upon a rigid body, keep it in equilibrium, then they must either
A meet in a point
B be all parallel
C at least two of them must meet
D all the above are correct

Answer: all the above are correct
42 A single force and a couple acting in the same plane upon a rigid body
A balance each other
B cannot balance each other
C produce moment of a couple
D are equivalent

43 The maximum frictional force which comes into play when a body just begins to slide over another surface is called
A limiting friction
B dynamic friction
C sliding friction
D rolling friction

44 The co-efficient of friction depends upon
A nature of surfaces
B area of contact
C shape of the surfaces
D ail of the above.

45 The effort required to lift a load W on a screw jack with helix angle a and angle of friction <j) is equal to
A Wtan(a + )
B Wtan(a-)
C Wcos(a + )
D Wsin(a + )

46 Kinetic friction is the
A tangent of angle between normal reaction and the resultant of normal reaction and the limiting friction
B ratio of limiting friction and normal reaction
C the friction force acting when the body is just about to move
D the friction force acting when the body is in motion

Answer: the friction force acting when the body is in motion
47 Tangent of angle of friction is equal to
A kinetic friction
B limiting friction
C angle of repose
D coefficient of friction

48 Dynamic friction as compared to static friction is
A same
B more
C less
D may be less of more depending on nature of surfaces and velocity

49 Coulomb friction is the friction between
A bodies having relative motion
B two dry surfaces
C two lubricated surfaces
D solids and liquids

50 Limiting force of friction is the
A tangent of angle between normal-reaction and the resultant of normal reaction and limiting friction
B ratio of limiting friction and normal reaction
C the friction force acting when the body is just about to move
D the friction force acting when the body is in motion

Answer: the friction force acting when the body is just about to move
51 If rain is falling in the opposite direction of the movement of a pedestrain, he has to hold his umbrella
A more inclined when moving
B less inclined when moving
C more inclined when standing
D less inclined when standing

52 A particle moves along a straight line such that distance (x) traversed in t seconds is given by x = t2 (t – 4), the acceleration of the particle will be given by the equation
A 3t2-lt
B 3t2+2t
C 6f-8
D 6f-4

53 Pick up wrong statement about friction force for dry surfaces. Friction force is
A proportional to normal load between the surfaces
B dependent on the materials of contact surface
C proportional to velocity of sliding
D independent of the area of contact surfaces

Answer: proportional to velocity of sliding
54 Coefficient of friction is the
A angle between normal reaction and the resultant of normal reaction and the limiting friction
B ratio of limiting friction and normal reaction
C the friction force acting when the body is just about to move
D the friction force acting when the body is in motion

Answer: ratio of limiting friction and normal reaction
55 Frictional force encountered after commencement of motion is called
A post friction
B limiting friction
C kinematic friction
D dynamic friction

56 On the ladder resting on the ground and leaning against a smooth vertical wall, the force of friction will be
A downwards at its upper end
B upwards at its upper end
C perpendicular to the wall at its upper end
D zero at its upper end

57 On a ladder resting on smooth ground and leaning against vertical wall, the force of friction will be
A towards the wall at its upper end
B away from the wall at its upper end
C upwards at its upper end
D downwards at its upper end

Answer: upwards at its upper end
58 Which one of the following statements is not correct
A the tangent of the angle of friction is equal to coefficient of friction
B the angle of repose is equal to angle of friction
C the tangent of the angle of repose is equal to coefficient of friction
D the sine of the angle of repose is equal to coefficient to friction

Answer: the sine of the angle of repose is equal to coefficient to friction
59 The ratio of limiting friction and normal reaction is known as
A coefficient of friction
B angle of friction
C angle of repose
D sliding friction