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4

The resultant of the following three couples 20 kg force, 0.5 m arm, +ve sense 30 kg force, 1 m arm, -ve sense 40 kg force, 0.25 m arm, +ve sense having arm of 0.5 m will be

A. 20 kg, -ve sense

B. 20 kg, + ve sense

C. 10 kg, + ve sense

D. 10 kg, -ve sense

Correct Answer :

A. 20 kg, -ve sense


Related Questions

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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

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4

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

A. Equal to

B. Less than

C. Greater than

D. None of these

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4

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

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4

A semicircular disc rests on a horizontal surface with its top flat surface horizontal and circular portion touching down. The coefficient of friction between semi circular disc and horizontal surface is μ. This disc is to be pulled by a horizontal force applied at one edge and it always remains horizontal. When the disc is about to start moving, its top horizontal force will

A. Remain horizontal

B. Slant up towards direction of pull

C. Slant down towards direction of pull

D. None of the above

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4

The law of motion involved in the recoil of gun is

A. Newton's first law of motion

B. Newton's second law of motion

C. Newton's third law of motion

D. None of these

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4

The moment of inertia of a sphere of mass m and radius r, about an axis tangential to it, is

A. 2mr2/3

B. 2mr2/5

C. 7mr2/3

D. 7mr2/5

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4

The velocity ratio for the first system of pulleys is (where n is the number of pulleys.)

A. n

B.

C. 2n

D. 2n - 1

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4

Mass moment of inertia of a uniform thin rod of mass M and length (l) about its mid-point and perpendicular to its length is

A. (2/3) Ml2

B. (1/3) Ml2

C. (3/4) Ml2

D. (1/12) Ml2

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4

A lead ball with a certain velocity is made to strike a wall, it falls down, but rubber ball of same mass and with same velocity strikes the same wall, it rebounds. Select the correct reason from the following:

A. Both the balls undergo an equal change in momentum

B. The change in momentum suffered by rubber ball is more than the lead ball

C. The change in momentum suffered by rubber ball is less than the lead ball

D. None of the above

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4

The range of projectile (R) on an upward inclined plane is

A. g. cos² β/2u². sin (α + β). cos α

B. 2u². sin (α + β). cos α/g. cos² β

C. g. cos² β/2u². sin (α - β). cos α

D. 2u². sin (α - β). cos α/g. cos² β

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4

Joule is the unit of

A. Force

B. Work

C. Power

D. Velocity

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4

If u1 and u2 are the velocities of two moving bodies in the same direction before impact and v1 and v2 are their velocities after impact, then coefficient of restitution is given by

A. (v1 - v2)/(u1 - u2)

B. (v₂ - v₁)/(u1 - u2)

C. (u1 - u2)/(v1 - v2)

D. (u₂ + u₁)/(v₂ + v₁)

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4

A pair of smith's tongs is an example of the lever of

A. Zeroth order

B. First order

C. Second order

D. Third order

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4

Frictional force encountered after commencement of motion is called

A. Limiting friction

B. Kinematic friction

C. Frictional resistance

D. Dynamic friction

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4

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

A. All the forces are equally inclined

B. Sum of all the forces is zero

C. Sum of resolved parts in the vertical direction is zero (i.e. ΣV = 0)

D. None of these

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4

Moment of inertia of a hollow rectangular section as shown in the below figure about X-X axis, is

A. (BD³/12) - (bd³/12)

B. (DB³/12) - (db³/12)

C. (BD³/36) - (bd³/36)

D. (DB³/36) - (db³/36)

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4

The range of a projectile is maximum, when the angle of projection is

A. 30°

B. 45°

C. 60°

D. 90°

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4

According to principle of moments

A. If a system of coplanar forces is in equilibrium, then their algebraic sum is zero

B. If a system of coplanar forces is in equilibrium, then the algebraic sum of their moments about any point in their plane is zero

C. The algebraic sum of the moments of any two forces about any point is equal to moment of the resultant about the same point

D. Positive and negative couples can be balanced

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4

When a person, on a bicycle, drives round a curve, he has to lean __________ to maintain equilibrium.

A. Inward

B. Outward

C. Towards front

D. Towards back

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4

In order to completely specify angular displacement by a vector, it must fix

A. Direction of the axis of rotation

B. Magnitude of angular displacement

C. Sense of angular displacement

D. All of these

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4

The centre of percussion of a solid cylinder of radius r resting on a horizontal plane will be

A. r/2

B. 2r/3

C. r/A

D. 3r/2

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4

Which of the following is not a vector quantity?

A. Weight

B. Velocity

C. Acceleration

D. Force

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4

A framed structure is perfect if it contains members equal to

A. 2n³

B. 2n

C.

D. 3n² Where n = number of joints in a frame

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4

Two bodies of masses m1 and m2 are hung from the ends of a rope, passing over a frictionless pulley as shown in the figure below. The acceleration of the string will be

A. g (m1 - m2)/(m1 + m2)

B. 2g (m1 - m2)/(m1 + m2)

C. g (m1 + m2)/(m1 - m2)

D. 2g (m1 + m2)/(m1 - m2)

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4

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

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4

The moment of the force P about O as shown in the below figure is

A. P × OA

B. P × OB

C. P × OC

D. P × AC

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4

The forces, whose lines of action are parallel to each other and act in the same directions, are known as

A. Coplanar concurrent forces

B. Coplanar non-concurrent forces

C. Like parallel forces

D. Unlike parallel forces

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4

The equivalent length of a simple pendulum which gives the same frequency as compound pendulum is

A. h/(kG² + h²)

B. (kG² + h²)/h

C. h²/(kG² + h²)

D. (kG² + h²)/h²

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4

The algebraic sum of moments of the forces forming couple about any point in their plane is

A. Equal to the moment of the couple

B. Constant

C. Both of above are correct

D. Both of above are wrong

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4

The centre of gravity of a uniform lamina lies at

A. The centre of heavy portion

B. The bottom surface

C. The midpoint of its axis

D. All of the above