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.)
t = g cos β/2u sin (α - β)
t = 2u sin (α - β)/g cos β
t = g cos β/2u sin (α + β)
t = 2u sin (α + β)/g cos β
Correct Answer :
B. t = 2u sin (α - β)/g cos β
Related Questions
Coplanar non-concurrent forces are those forces which __________ at one point, but their lines of action lie on the same plane.
Meet
Do not meet
Either A or B
None of these
The unit of force in S.I. units is
kilogram
Newton
Watt
Dyne
The rate of change of displacement of a body is called
Velocity
Acceleration
Momentum
None of these
Which of the following is not the unit of work, energy and heat?
kcal
kg-m
kW-hr
h.p
Least force required to draw a body up the inclined plane is W sin (plane inclination + friction angle) applied in the direction
Along the plane
Horizontally
Vertically
At an angle equal to the angle of friction to the inclined plane
Which of the following is not a vector quantity?
Weight
Velocity
Acceleration
Force
A particle moves along a straight line such that distance (x) traversed in t seconds is given by x = t² (t - 4), the acceleration of the particle will be given by the equation
6t² - 8t
3t² + 2t
6f - 8
6f - 4
The necessary condition for forces to be in equilibrium is that these should be
Coplanar
Meet at one point
Both (A) and (B) above
All be equal
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.)
P = mW - C
P = m/W + C
P = mW + C
P = C - mW
A machine having an efficiency greater than 50%, is known as
Reversible machine
Non-reversible machine
Neither reversible nor non-reversible machine
Ideal machine
The term 'Centroid' is
The same as centre of gravity
The point of suspension
The point of application of the resultant of all the forces tending to cause a body to rotate about a certain axis
None of the above
If a body is acted upon by a number of coplanar non-concurrent forces, it may
Rotate about itself without moving
Move in any one direction rotating about itself
Be completely at rest
All of these
In order to double the period of simple pendulum, the length of the string should be
Halved
Doubled
Quadrupled
None of these
Frictional force encountered after commencement of motion is called
Limiting friction
Kinematic friction
Frictional resistance
Dynamic friction
A heavy ladder resting on floor and against a vertical wall may not be in equilibrium, if
The floor is smooth, the wall is rough
The floor is rough, the wall is smooth
The floor and wall both are smooth surfaces
The floor and wall both are rough surfaces
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. 
Will
Will not
Either A or B
None of these
The motion of a wheel of a car is
Purely translation
Purely rotational
Combined translation and rotational
None of these
According to the law of moments, 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.
The velocity ratio for the third system of pulleys is
n
n²
2n
2n - 1
A flywheel on a motor goes from rest to 1000 rpm in 6 sec. The number of revolutions made is nearly equal to
25
50
100
250
The moment of the force P about O as shown in the below figure is 
P × OA
P × OB
P × OC
P × AC
Which of the following statement is correct?
The kinetic energy of a body during impact remains constant.
The kinetic energy of a body before impact is equal to the kinetic energy of a body after impact.
The kinetic energy of a body before impact is less than the kinetic energy of a body after impact.
The kinetic energy of a body before impact is more than the kinetic energy of a body after impact.
D' Alembert's principle is used for
Reducing the problem of kinetics to equivalent statics problem
Determining stresses in the truss
Stability of floating bodies
Designing safe structures
The wheels of a moving car possess
Potential energy only
Kinetic energy of translation only
Kinetic energy of rotation only
Kinetic energy of translation and rotation both
If a number of forces are acting at a point, their resultant is given by
(ΣV)2 + (ΣH)2
√[(ΣV)2 + (ΣH)2]
(ΣV)2 +(ΣH)2 +2(ΣV)(ΣH)
√[(ΣV)2 +(ΣH)2 +2(ΣV)(ΣH)]
Moment of inertia of a hollow circular section, as shown in the below figure about an axis perpendicular to the section, is __________ than that about X-X axis. 
Two times
Same
Half
None of these
The maximum efficiency of a lifting machine is
1/m
V.R./m
m/V.R.
1/(m × V.R.)
The potential energy of a vertically raised body is __________ the kinetic energy of a vertically falling body.
Equal to
Less than
Greater than
None of these
A framed structure is perfect, if the number of members are __________ (2j - 3), where j is the number of joints.
Equal to
Less than
Greater than
None of these
The force induced in the string AB due to the load W, as shown in the below figure is 
W sinθ
W cosθ
W secθ
W cosecθ