Three forces acting on a rigid body are represented in magnitude, direction and line of action by the three sides of a triangle taken in order. The forces are equivalent to a couple whose moment is equal to
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
Efficiency of a screw jack is given by(where α = Helix angle, and φ = Angle of friction.)
When a train is rounding a curve, the side thrust on the wheel flanges is prevented by raising the outer edge of the rail.
Frequency of vibrations means the number of cycles per second.
The time of flight (t) of a projectile on a horizontal plane is given by
The velocity ratio for the third system of pulleys is
The moment of inertia of a thin spherical shell of mass m and radius r, about its diameter is
If the gravitational acceleration at any place is doubled, then the weight of a body will be
Correct Answer :- d
Explanation : Weight = density * acceleration
If the gravitational acceleration at any place is doubled, then the weight of a body will be doubled.
The resultant of two forces P and Q (such that P > Q) acting along the same straight line, but in opposite direction, is given by
The velocity ratio for the second system of pulleys is n.
The law of motion involved in the recoil of gun is
When a particle moves along a circular path, its acceleration has two components, one is normal component and the other is tangential component of acceleration.
A machine which is not capable of doing any work in the reversed direction, after the effort is removed, is called a reversible machine.
The range of projectile will be maximum for a given velocity of projectile, when the angle of projection (α) is
When two elastic bodies collide with each other,
In order to double the period of simple pendulum, the length of the string should be
The centre of gravity of a triangle lies at a point where its medians intersect each other.
The moment of inertia of a square of side a about its base is a4/ 3.
If the number of pulleys in a system is equal to its velocity ratio, then it is a __________ system of pulleys
The centre of gravity of a right angled triangle lies at its geometrical centre.
Vectors method for the resultant force is also called polygon law of forces.
Two equal and opposite parallel forces whose lines of action are different form a couple.
When a person, on a bicycle, drives round a curve, he has to lean __________ to maintain equilibrium.
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 centre of gravity of the section will lie