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4

The moment of inertia of a thin disc of mass m and radius r, about an axis through its centre of gravity and perpendicular to the plane of the disc is

A. mr2/2

B. mr2/4

C. mr2/6

D. mr2/8

Correct Answer :

A. mr2/2


Related Questions

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4

The law of the machine is (where P = Effort applied to lift the load, m = A constant which is equal to the slope of the line, W = Load lifted, and C = Another constant which represents the machine friction.)

A. P = mW - C

B. P = m/W + C

C. P = mW + C

D. P = C - mW

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4

The total energy possessed by a system of moving bodies

A. Is constant at every instant

B. Varies from point to point

C. Is maximum in the start and minimum at the end

D. Is minimum in the start and maximum at the end

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4

Which of the following statement is correct in connection with projectiles?

A. A path, traced by a projectile in the space, is known as trajectory.

B. The velocity, with which a projectile is projected, is known as the velocity of projection.

C. The angle, with the horizontal, at which a projectile is projected, is known as angle of projection.

D. All of the above

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4

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

A. 5

B. 10

C. 20

D. 40

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4

Which of the following are vector quantities?

A. Angular displacement

B. Angular velocity

C. Angular acceleration

D. All of these

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4

Center of percussion is

A. The point of C.G.

B. The point of metacenter

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

D. Point of suspension

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4

The friction experienced by a body, when at rest, is known as

A. Static friction

B. Dynamic friction

C. Limiting friction

D. Coefficient of friction

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4

A force is completely defined when we specify

A. Magnitude

B. Direction

C. Point of application

D. All of the above

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4

Two blocks A and B of masses 150 kg and 50 kg respectively are connected by means of a string as shown in the below figure. The tension in all the three strings __________ be same.

A. Will

B. Will not

C. Either A or B

D. None of these

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4

If n = number of members and y = number of joints, then for a perfect frame, n = ?

A. 1/2

B. 2/3

C. 3/2

D. 2/4

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4

The forces, which meet at one point and their lines of action also lie on the same plane, are known as

A. Coplanar concurrent forces

B. Coplanar non-concurrent forces

C. Non-coplanar concurrent forces

D. Non-coplanar non-concurrent forces

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4

Which of the following is a vector quantity?

A. Energy

B. Mass

C. Momentum

D. Angle

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4

The centre of gravity of a right circular solid cone is at a distance of __________ from its base, measured along the vertical axis. (where h = Height of a right circular solid cone.)

A. h/2

B. h/3

C. h/4

D. h/6

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4

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

A. πN/60

B. πN/180

C. 2πN/60

D. 2πN/180

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4

The unit of force in S.I. units is

A. kilogram

B. Newton

C. Watt

D. Dyne

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4

A pendulum which executes one beat per second is known as

A. Simple pendulum

B. Compound pendulum

C. Torsional pendulum

D. Second's pendulum

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4

The unit of force in S.I. system of units is

A. Dyne

B. Kilogram

C. Newton

D. Watt

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4

Which of the following is the example of lever of first order?

A. Arm of man

B. Pair of scissors

C. Pair of clinical tongs

D. All of the above

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4

The coefficient of friction depends upon

A. Nature of surfaces

B. Area of contact

C. Shape of the surfaces

D. All of the above

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4

A flywheel on a motor goes from rest to 1000 rpm in 6 sec. The number of revolutions made is nearly equal to

A. 25

B. 50

C. 100

D. 250

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4

Efficiency of a screw jack is given by (where α = Helix angle, and φ = Angle of friction.)

A. tan(α + φ)/tanα

B. tanα/tan (α + φ)

C. tan(α - φ)/tanα

D. None of these

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4

One watt is equal to

A. 0.1 joule/s

B. 1 joule/s

C. 10 joules/s

D. 100 joules/s

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4

The time of flight (t) of a projectile on an upward inclined plane is (where u = Velocity of projection, α = Angle of projection, and β = Inclination of the plane with the horizontal.)

A. t = g cos β/2u sin (α - β)

B. t = 2u sin (α - β)/g cos β

C. t = g cos β/2u sin (α + β)

D. t = 2u sin (α + β)/g cos β

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4

The maximum efficiency of a screw jack is

A. (1 - sinφ)/(1 + sinφ)

B. (1 + sinφ)/(1 - sinφ)

C. (1 - tanφ)/(1 + tanφ)

D. (1 + tanφ)/(1 - tanφ)

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4

When trying to turn a key into a lock, following is applied

A. Coplanar force

B. Non-coplanar forces

C. Moment

D. Couple

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4

The friction experienced by a body, when in motion, is known as

A. Rolling friction

B. Dynamic friction

C. Limiting friction

D. Static friction

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4

The force induced in the string AB due to the load W, as shown in the below figure is

A. W sinθ

B. W cosθ

C. W secθ

D. W cosecθ

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4

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

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4

The unit of angular acceleration is

A. N-m

B. m/s

C. m/s2

D. rad/s2

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4

The acceleration of a body sliding down an inclined surface is

A. g sinθ

B. g cosθ

C. g tanθ

D. None of these