# Engineering Mechanics MCQ Mechanical Engineering

50 Questions 30 Mins

Following are some of the multiple choice questions on the Engineering Mechanics with answers that will help the students in developing their knowledge.

## Engineering Mechanics MCQ

### 1. Coefficient of friction depends upon

• Area of contact only
• Nature of surface only
• Both (A) and (B)
• None of these

### 2. According to law of triangle of forces

• Three forces acting at a point will be in equilibrium
• Three forces acting at a point can be represented by a triangle, each side being proportional to force
• If three forces acting upon a particle are represented in magnitude and direction by the sides of a triangle, taken in order, they will be in equilibrium
• If three forces acting at a point are in equilibrium, each force is proportional to the sine of the angle between the other two

### 3. An ideal machine is one whose efficiency is

• Between 60 and 70 %
• Between 70 and 80%
• Between 80 and 90%
• 100%

• 1 + m
• 1 - m
• 1 / m
• m

### 5. In the equation of virtual work, following force is neglected

• Reaction of any smooth surface with which the body is in contact
• Reaction of a rough surface of a body which rolls on it without slipping
• Reaction at a point or an axis, fixed in space, around which a body is constrained to turn
• All of the above

### 6. A heavy ladder resting on floor and against a vertical wall may not be in equilibrium, if

• The floor is smooth, the wall is rough
• The floor is rough, the wall is smooth
• The floor and wall both are smooth surfaces
• The floor and wall both are rough surfaces

### 7. When two elastic bodies collide with each other,

• The two bodies will momentarily come to rest after collision
• The two bodies tend to compress and deform at the surface of contact
• The two bodies begin to regain their original shape
• All of the above

### 8. A number of forces acting at a point will be in equilibrium, if

• All the forces are equally inclined
• Sum of all the forces is zero
• Sum of resolved parts in the vertical direction is zero (i.e. ∑V = 0)
• None of these

• a4/4
• a4/8
• a4/12
• a4/36

• P/2
• 2P
• √2 × P
• P/√2

### 11. A smooth cylinder lying on its convex surface remains in __________ equilibrium.

• Stable
• Unstable
• Neutral
• None of these

• ω/r
• ω.r
• ω²/r
• ω².r

### 13. During elastic impact, the relative velocity of the two bodies after impact is __________ the relative velocity of the two bodies before impact.

• Equal to
• Equal and opposite to
• Less than
• Greater than

### 14. For a self locking machine, the efficiency must be

• Equal to 50%
• Less than 50%
• Greater than 50%
• 100%

### 15. According to Newton's first law of motion,

• Everybody continues in its state of rest or of uniform motion, in a straight line, unless it is acted upon by some external force
• The rate of change of momentum is directly proportional to the impressed force, and takes place in the same direction, in which the force acts
• To every action, there is always an equal and opposite reaction
• None of the above

### 16. The force required to move the body up the plane will be minimum if it makes an angle with the inclined plane __________ the angle of friction.

• Equal to
• Less than
• Greater than
• None of these

### 17. Angle of friction is the

• Angle between normal reaction and the resultant of normal reaction and the limiting friction
• Ratio of limiting friction and normal reaction
• The ratio of minimum friction force to the friction force acting when the body is just about to move
• The ratio of minimum friction force to friction force acting when the body is in motion

### 18. If tension in the cable supporting a lift moving downwards is half the tension when it is moving upwards, the acceleration of the lift is

• g/2
• g/3
• g/4
• None of these

• 6t² - 8t
• 3t² + 2t
• 6f - 8
• 6f - 4

### 20. Center of percussion is

• The point of G.
• The point of metacenter
• The point of application of the resultant of all the forces tending to cause a body to rotate about a certain axis
• Point of suspension

### 21. Coefficient of friction is the

• Angle between normal reaction and the resultant of normal reaction and the limiting friction
• Ratio of limiting friction and normal reaction
• The friction force acting when the body is just about to move
• The friction force acting when the body is in motion

### 22. The ratio of limiting friction and normal reaction is known as

• Coefficient of friction
• Angle of friction
• Angle of repose
• Sliding friction

### 23. Least force required to draw a body up the inclined plane is W sin (plane inclination + friction angle) applied in the direction

• Along the plane
• Horizontally
• Vertically
• At an angle equal to the angle of friction to the inclined plane

### 24. Non-coplanar concurrent forces are those forces which

• Meet at one point, but their lines of action do not lie on the same plane
• Do not meet at one point and their lines of action do not lie on the same plane
• Meet at one point and their lines of action also lie on the same plane
• Do not meet at one point, but their lines of action lie on the same plane

### 25. Coplanar concurrent forces are those forces which

• Meet at one point, but their lines of action do not lie on the same plane
• Do not meet at one point and their lines of action do not lie on the same plane
• Meet at one point and their lines of action also lie on the same plane
• Do not meet at one point, but their lines of action lie on the same plane

### 26. Non-coplanar non-concurrent forces are those forces which

• Meet at one point, but their lines of action do not lie on the same plane
• Do not meet at one point and their lines of action do not lie on the same plane
• Do not meet at one point but their lines of action lie on the same plane
• None of the above

### 27. A pendulum which executes one beat per second is known as

• Simple pendulum
• Compound pendulum
• Torsional pendulum
• Second's pendulum

### 28. D' Alembert's principle is used for

• Reducing the problem of kinetics to equivalent statics problem
• Determining stresses in the truss
• Stability of floating bodies
• Designing safe structures

### 29. Centre of gravity of a solid cone lies on the axis at the height

• One fourth of the total height above base
• One third of the total height above base
• One-half of the total height above base
• Three eighth of the total height above the base

### 30. In the lever of third order, load ‘W’, effort ‘P’ and fulcrum ‘F’ are oriented as follows

• W between P and F
• F between W and P
• P between W and F
• W, P and F all on one side

### 31. The ideal angle of banking provided on the curves on roads depends upon

• Weight of the vehicle
• (Velocity)2 of the vehicle
• Nature of the road surface
• Coefficient of friction between the road and vehicle contact point

### 32. The power developed by a body acted upon by a torque 'T' Newton meter (N - m) and revolving at ω radian/s is given by

• T.ω (in watts)
• T.ω/60 (in watts)
• T.ω/75 (in kilowatts)
• T.ω/4500 (in kilowatts)

• W sinθ
• W cosθ
• W tanθ
• W cotθ

• 0.5 cm
• 1.0 cm
• 1.5 cm
• 2.5 cm

### 35. If rain is falling in the opposite direction of the movement of a pedestrian, he has to hold his umbrella

• More inclined when moving
• Less inclined when moving
• More inclined when standing
• Less inclined when standing

• ω
• ωr
• ω2r
• ω/r

### 37. Which of the following is an equation of linear motion?(where, u and v = Initial and final velocity of the body, a = Acceleration of the body, and s = Displacement of the body in time t seconds.)

• v = u + a.t
• s = u.t + ½ a.t2
• v2 = u2 + 2a.s
• All of these

• mr²/2
• mr²/4
• mr²/6
• mr²/8

### 39. If three forces acting in different planes can be represented by a triangle, these will be in

• Non-equilibrium
• Partial equilibrium
• Full equilibrium
• Unpredictable

• D/(d₁ + d₂)
• D/(d₁ - d₂)
• 2D/(d₁ + d₂)
• 2D/(d₁ - d₂)

### 41. A circular hole of 50 mm diameter is cut out from a circular disc of 100 mm diameter as shown in the below figure. The center of gravity of the section will lie

• In the hole
• At ‘O’
• None of these

• 2n³
• 2n
• 3n²

• D + d
• D - d
• D × d
• D / d

### 44. A screw jack used for lifting the loads is

• A reversible machine
• A non-reversible machine
• An ideal machine
• None of these

### 45. The coefficient of restitution for inelastic bodies is

• Zero
• One
• Between zero and one
• More than one

### 46. Which of the following statement is correct?

• The periodic time of a particle moving with simple harmonic motion is the time taken by a particle for one complete oscillation
• The periodic time of a particle moving with simple harmonic motion is directly proportional to its angular velocity
• The velocity of the particle moving with simple harmonic motion is zero at the mean position
• The acceleration of the particle moving with simple harmonic motion is maximum at the mean position

• Energy
• Mass
• Momentum
• Angle

• Force
• Speed
• Velocity
• Acceleration

• 25
• 50
• 100
• 250

### 50. The centre of gravity of a uniform lamina lies at

• The centre of heavy portion
• The bottom surface
• The midpoint of its axis
• All of the above