R4RIN – MCQs, Mock Tests | Engineering Mechanical Engineering Engineering MCQS -Mechanics Section-2

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

1. moment of inertia
2. centre of gravity
3. centre of percussion
4. centre of mass

✅ Correct Answer: 2

Which of the following is a scalar quantity?

1. Force
2. Speed
3. Velocity
4. Acceleration

✅ Correct Answer: 2

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. This statement is known as

1. Newton's first law of motion
2. Newton's second law of motion
3. Newton's third law of motion
4. none of these

✅ Correct Answer: 2

In ideal machines, mechanical advantage is __________ velocity ratio.

1. equal to
2. less than
3. greater than
4. none of these

✅ Correct Answer: 1

The minimum force required to slide a body of weight W on a rough horizontal plane is

1. W sin θ
2. W cos θ
3. W tan θ
4. none of these

✅ Correct Answer: 3

The angular velocity (in rad / s) of a body rotating at N revolutions per minute is

1. πN/60
2. πN/180
3. 2πN/60
4. 2πN/180

✅ Correct Answer: 3

The maximum efficiency of a lifting machine is

1. 1/m
2. V.R./m
3. m/V.R.
4. 1/(m x V.R.)

✅ Correct Answer: 4

The centre of gravity of a semi-circle lies at a distance of __________ from its base measured along the vertical radius.

1. 3r/ 8
2. 4r/ 3π
3. 8r/3
4. 3r/4π

✅ Correct Answer: 2

A weight of 1000 N can be lifted by an effort of 80 N. If the velocity ratio is 20, the machine is

1. reversible
2. non-reversible
3. ideal
4. none of these

✅ Correct Answer: 1

The potential energy of a vertically raised body is __________ the kinetic energy of a vertically falling body.

1. equal to
2. . less than
3. greater than
4. none of these

✅ Correct Answer: 1

The motion of a particle round a fixed axis is

1. translatory
2. rotary
3. circular
4. translatory as well as rotatry

✅ Correct Answer: 3

The principle of transmissibility of forces states that, when a force acts upon a body, its effect is

1. same at every point on its line of action
2. different at different points on its line of action
3. minimum, if it acts at the centre of gravity of the body
4. minimum, if it acts at the centre of gravity of the body

✅ Correct Answer: 3

A differential pulley block has larger and smaller diameters of 100 mm and 80 mm respectively. Its velocity ratio is

1. 5
2. 10
3. 20
4. 40

✅ Correct Answer: 2

Which of the following are vector quantities?

1. Linear displacement
2. Linear velocity
3. Linear acceleration
4. all of these

✅ Correct Answer: 4

Non-coplaner concurrent forces are those forces which

1. meet at one point, but their lines of action do not lie on the same plane
2. do not meet at one point and their lines of action do not lie on the same plane
3. meet at one point and their lines of action also lie on the same plane
4. do not meet at one point, but their lines of action lie on the same plane

✅ Correct Answer: 1

Which of the following statement is correct?

1. The kinetic energy of a body during impact remains constant.
2. The kinetic energy of a body before impact is equal to the kinetic energy of a body after impact.
3. The kinetic energy of a body before impact is less than the kinetic energy of a body after impact.
4. The kinetic energy of a body before impact is more than the kinetic energy of a body after impact.

✅ Correct Answer: 4

Concurrent forces are those forces whose lines of action

1. lie on the same line
2. meet at one point
3. meet on the same plane
4. none of these

✅ Correct Answer: 2

According to the law of moments, if a number of coplaner forces acting on a particle are in equilibrium, then

1. their algebraic sum is zero
2. their lines of action are at equal distances
3. the algebraic sum of their moments about any point in their plane is zero
4. the algebraic sum of their moments about any point is equal to the moment of their resultant force about the same point.

✅ Correct Answer: 3

A machine having an efficiency less than 50%, is known as

1. reversible machine
2. non-reversible machine
3. neither reversible nor non-reversible machine
4. ideal machine

✅ Correct Answer: 2

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

1. Newton's first law of motion
2. Newton's second law of motion
3. principle of conservation of energy
4. principle of conservation of energy

✅ Correct Answer: 4

A rubber ball is dropped from a height of 2 m. If there is no loss of velocity after rebounding, the ball will rise to a height of

1. 1m
2. 2m
3. 3m
4. 4m

✅ Correct Answer: 2

When the spring of a watch is wound, it will possess

1. strain energy
2. kinetic energy
3. heat energy
4. electrical energy

✅ Correct Answer: 1

The rate of doing work is known as

1. potential energy
2. kinetic energy
3. power
4. none of these

✅ Correct Answer: 3

The unit of work in S.I. units is

1. newton
2. erg
3. kg-m
4. joule

✅ Correct Answer: 4

The static friction

1. bears a constant ratio to the normal reaction between the two surfaces
2. is independent of the area of contact, between the two surfaces
3. always acts in a direction, opposite to that in which the body tends to move
4. all of the above

✅ Correct Answer: 4

The acceleration of a particle moving with simple harmonic motion is __________ at themean position.

1. zero
2. minimum
3. maximum
4. none of these

✅ Correct Answer: 1

The velocity of a particle moving with simple harmonic motion is __________ at the mean position.

1. zero
2. minimum
3. maximum
4. none of these

✅ Correct Answer: 3

A framed structure is imperfect, if the number of members are __________ (2j - 3).

✅ Correct Answer: 4

The total energy possessed by a system of moving bodies

1. is constant at every instant
2. varies from point to point
3. is maximum in the start and minimum at the end
4. is minimum in the start and maximum at the end

✅ Correct Answer: 1

A couple produces

1. translatory motion
2. rotational motion
3. combined translatory and rotational motion
4. none of the above

✅ Correct Answer: 2

For a self locking machine, the efficiency must be

1. equal to 50%
2. less than 50%
3. greater than 50%
4. 100%

✅ Correct Answer: 2

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

1. P = Q
2. Q = R
3. Q = R
4. none of these

✅ Correct Answer: 2

Onejoule is equal to

1. 0.1 N-m
2. 1 N-m
3. 10 N-m
4. 100 N-m

✅ Correct Answer: 2

Whenever a force acts on a body and the body undergoes a displacement, then

1. work is said to be done
2. work is said to be done
3. body has kinetic energy of translation
4. none of these

✅ Correct Answer: 1

The rate of change of displacement of a body is called

1. velocity
2. acceleration
3. momentum
4. none of these

✅ Correct Answer: 1