Forces are called coplanar when all of them acting on body lie in
One point
One plane
Different planes
Perpendicular planes
Correct Answer :
B. One plane
Related Questions
Limiting force of friction is the
Tangent of angle between normal reaction and the resultant of normal reaction and 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
The three forces of 100 N, 200 N and 300 N have their lines of action parallel to each other but act in the opposite directions. These forces are known as
Coplanar concurrent forces
Coplanar non-concurrent forces
Like parallel forces
Unlike parallel forces
In actual machines, mechanical advantage is __________ velocity ratio.
Equal to
Less than
Greater than
None of these
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
When the spring of a watch is wound, it will possess
Strain energy
Kinetic energy
Heat energy
Electrical energy
The slope on the road surface generally provided on the curves is known as
Angle of friction
Angle of repose
Angle of banking
None of these
Efficiency of a screw jack is given by (where α = Helix angle, and φ = Angle of friction.)
tan(α + φ)/tanα
tanα/tan (α + φ)
tan(α - φ)/tanα
None of these
A ladder is resting on a smooth ground and leaning against a rough vertical wall. The force of friction will act
Towards the wall at its upper end
Away from the wall at its upper end
Downward at its upper end
Upward at its upper end
The overturning of a vehicle on a level circular path can be avoided if the velocity of vehicle is __________ √(gra/h)
Less than
Greater than
Equal to
None of these
When trying to turn a key into a lock, following is applied
Coplanar force
Non-coplanar forces
Moment
Couple
If a suspended body is struck at the centre of percussion, then the pressure on die axis passing through the point of suspension will be
Maximum
Minimum
Zero
Infinity
In determining stresses in frames by methods of sections, the frame is divided into two parts by an imaginary section drawn in such a way as not to cut more than
Two members with unknown forces of the frame
Three members with unknown forces of the frame
Four members with unknown forces of the frame
Three members with known forces of the frame
Which of the following are vector quantities?
Angular displacement
Angular velocity
Angular acceleration
All of these
The angular velocity (in rad/s) of a body rotating at N revolutions per minute is
πN/60
πN/180
2πN/60
2πN/180
The unit of power in S.I. units is
Horsepower
Joule
Watt
kg-m
The total energy possessed by a system of moving bodies
Is constant at every instant
Varies from point to point
Is maximum in the start and minimum at the end
Is minimum in the start and maximum at the end
The moment of inertia of a square of side a about its diagonal is
a2/8
a3/12
a4/12
a4/16
Which of the following is not the unit of work, energy and heat?
kcal
kg-m
kW-hr
h.p
Which is the correct statement about law of polygon of forces?
If any number of forces acting at a point can be represented by the sides of a polygon taken in order, then the forces are in equilibrium
If any number of forces acting at a point can be represented in direction and magnitude by the sides of a polygon, then the forces are in equilibrium
If a polygon representing forces acting at a point is closed then forces are in equilibrium
If any number of forces acting at a point can be represented in direction and magnitude by the sides of a polygon taken in order, then the forces are in equilibrium
Which of the following statement is correct in connection with projectiles?
A path, traced by a projectile in the space, is known as trajectory.
The velocity, with which a projectile is projected, is known as the velocity of projection.
The angle, with the horizontal, at which a projectile is projected, is known as angle of projection.
All of the above
From a circular plate of diameter 6 cm is cut out a circle whose diameter is a radius of the plate. Find the e.g. of the remainder from the centre of circular plate
0.5 cm
1.0 cm
1.5 cm
2.5 cm
For a self locking machine, the efficiency must be
Equal to 50 %
Less than 50 %
Greater than 50 %
100 %
The ratio of limiting friction and normal reaction is known as
Coefficient of friction
Angle of friction
Angle of repose
Sliding friction
The unit of work or energy in S.I. units is
Newton
Pascal
Watt
Joule
The unit of angular velocity is
m/min
rad/s
Revolutions/min
Both (B) and (C)
Tangent of angle of friction is equal to
Kinetic friction
Limiting friction
Angle of repose
Coefficient of friction
Coulomb friction is the friction between
Bodies having relative motion
Two dry surfaces
Two lubricated surfaces
Solids and liquids
The coefficient of restitution for inelastic bodies is
Zero
One
Between zero and one
More than one
Two forces are acting at an angle of 120°. The bigger force is 40 N and the resultant is perpendicular to the smaller one. The smaller force is
20 N
40 N
120 N
None of these
Dynamic friction as compared to static friction is
Same
More
Less
May be less of more depending on nature of surfaces and velocity