The bellow figure shows the three coplanar forces P, Q and R acting at a point O. If these forces are in equilibrium, then 
P/sin β = Q/sin α = R/sin
P/sin α = Q/sin β = R/sin
P/sin = Q/sin α = R/sin β
P/sin α = Q/sin = R/sin β
Correct Answer :
B. P/sin α = Q/sin β = R/sin
Related Questions
A block of mass m1, placed on an inclined smooth plane is connected by a light string passing over a smooth pulley to mass m2, which moves vertically downwards as shown in the below figure. The tension in the string is 
m1/m2
m1. g. sin α
m1.m2/m1 + m2
m1. m2.g (1 + sin α)/(m1 + m2)
The maximum acceleration of a particle moving with simple harmonic motion is
ω
ωr
ω2r
ω/r
The bodies which rebound after impact are called
Inelastic bodies
Elastic bodies
Neither elastic nor inelastic bodies
None of these
The rate of doing work is known as
Potential energy
Kinetic energy
Power
None of these
The velocity of a body on reaching the ground from a height h, is
2.√(gh)
√(gh)
√(2gh)
2g.√h
If two bodies having masses m1 and m2 (m1>m2) have equal kinetic energies, the momentum of body having mass m1 is _________ the momentum of body having mass m2.
Equal to
Less than
Greater than
None of these
If three forces acting in one plane upon a rigid body, keep it in equilibrium, then they must either
Meet in a point
Be all parallel
At least two of them must meet
All the above are correct
The force, by which the body is attracted, towards the centre of the earth, is called
Impulsive force
Mass
Weight
Momentum
The mechanical advantage of a lifting machine is the ratio of
Distance moved by effort to the distance moved by load
Load lifted to the effort applied
Output to the input
All of the above
For any system of coplanar forces, the condition of equilibrium is that the
Algebraic sum of the horizontal components of all the forces should be zero
Algebraic sum of the vertical components of all the forces should be zero
Algebraic sum of moments of all the forces about any point should be zero
All of the above
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
If a number of forces act simultaneously on a particle, it is possible
Not a replace them by a single force
To replace them by a single force
To replace them by a single force through C.G.
To replace them by a couple
Which of the following do not have identical dimensions?
Momentum and impulse
Torque and energy
Torque and work
Moment of a force and angular momentum.
The resultant of the two forces P and Q is R. If Q is doubled, the new resultant is perpendicular to P. Then
P = Q
Q = R
Q = 2R
None of these
The length of a second's pendulum is
94.9 cm
99.4 cm
100 cm
101 cm
The maximum mechanical advantage of a lifting machine is
1 + m
1 - m
1 / m
m
The coefficient of friction depends upon
Nature of surfaces
Area of contact
Shape of the surfaces
All of the above
A weight of 1000 N can be lifted by an effort of 80 N. If the velocity ratio is 20, the machine is
Reversible
Non-reversible
Ideal
None of these
Which of the following is not the unit of work, energy and heat?
kcal
kg-m
kW-hr
h.p
The motion of a particle round a fixed axis is
Translatory
Rotary
Circular
Translatory as well as rotary
When two elastic bodies collide with each other,
The two bodies will momentarily come to rest after collision
The two bodies tend to compress and deform at the surface of contact
The two bodies begin to regain their original shape
All of the above
If P is the force acting on the body, m is the mass of the body and a is the acceleration of the body, then according to Newton's second law of motion,
P + m.a = 0
P - m.a = 0
P × m.a = 0
P/m.a = 0
A framed structure is imperfect, if the numbers of members are __________ (2j - 3).
Equal to
Less than
Greater than
Either (B) or (C)
Which of the following is not a vector quantity?
Weight
Velocity
Acceleration
Force
The C.G. of a right circular solid cone of height h lies at the following distance from the base
h/2
J/3
h/6
h/4
The centre of gravity of a trapezium with parallel sides a and b lies at a distance of y from the base b, as shown in the below figure. The value of y is 
h [(2a + b)/(a + b)]
(h/2) [(2a + b)/(a + b)]
(h/3) [(2a + b)/(a + b)]
(h/3) [(a + b)/(2a + b)]
The acceleration of a particle moving with simple harmonic motion is __________ at the mean position.
Zero
Minimum
Maximum
None of these
Varingon's theorem of moments states that if a number of coplanar forces acting on a particle are in equilibrium, then
Their algebraic sum is zero
Their lines of action are at equal distances
The algebraic sum of their moments about any point in their plane is zero
The algebraic sum of their moments about any point is equal to the moment of their resultant force about the same point.
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 m
2 m
3 m
4 m
The maximum efficiency of a lifting machine is
1/m
V.R./m
m/V.R.
1/(m × V.R.)