The time of flight (t) of a projectile on a horizontal plane is given by
t = 2u. sinα/g
t = 2u. cosα/g
t = 2u. tanα/g
t = 2u/g.sinα
Correct Answer :
A. t = 2u. sinα/g
Related Questions
The moment of inertia of a thin rod of mass m and length l, about an axis through its centre of gravity and perpendicular to its length is
ml2/4
ml2/ 6
ml2/8
ml2/12
In a framed structure, as shown in the below figure, the forces in the members AB and BC are respectively 
√3. W (tensile) and 2W (compressive)
2W (tensile) and √3. W (compressive)
2√3. W (tensile) and 2√3. W (compressive)
None of the above
Which of the following is an equation of linear motion? (where, u and v = Initial and final velocity of the body, a = Acceleration of the body, and s = Displacement of the body in time t seconds.)
v = u + a.t
s = u.t + ½ a.t2
v2 = u2 + 2a.s
All of these
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 velocity of a particle moving with simple harmonic motion is __________ at the mean position.
Zero
Minimum
Maximum
None of these
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
The resultant of two equal forces P making an angle θ, is given by
2P sinθ/2
2P cosθ/2
2P tanθ/2
2P cotθ/2
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
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
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:
Both the balls undergo an equal change in momentum
The change in momentum suffered by rubber ball is more than the lead ball
The change in momentum suffered by rubber ball is less than the lead ball
None of the above
The maximum efficiency of a screw jack is
(1 - sinφ)/(1 + sinφ)
(1 + sinφ)/(1 - sinφ)
(1 - tanφ)/(1 + tanφ)
(1 + tanφ)/(1 - tanφ)
Frictional force encountered after commencement of motion is called
Limiting friction
Kinematic friction
Frictional resistance
Dynamic friction
The M.I. of hollow circular section about a central axis perpendicular to section as compared to its M.I. about horizontal axis is
Same
Double
Half
Four times
A framed structure, as shown in the below figure, is a 
Perfect frame
Deficient frame
Redundant frame
None of the above
Two balls of equal mass and of perfectly elastic material are lying on the floor. One of the balls with velocity v is made to strike the second ball. Both the balls after impact will move with a velocity
v
v/2
v/4
v/8
The angle of inclination of the plane at which the body begins to move down the plane, is called
Angle of friction
Angle of repose
Angle of projection
None of these
The weight of a body is due to
Gravitational pull exerted by the earth
Forces experienced by body in atmosphere
Force of attraction experienced by particles
Gravitational force of attraction towards the centre of the earth
Which of the following is not a vector quantity?
Weight
Velocity
Acceleration
Force
Which of the following is not a scalar quantity?
Mass
Volume
Density
Acceleration
In a single threaded worm and worm wheel, the number of teeth on the worm is 50. The diameter of the effort wheel is 100 mm and that of load drum is 50 mm. The velocity ratio is
50
100
200
400
Coulomb friction is the friction between
Bodies having relative motion
Two dry surfaces
Two lubricated surfaces
Solids and liquids
The bodies which rebound after impact are called
Inelastic bodies
Elastic bodies
Neither elastic nor inelastic bodies
None of these
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
Coefficient of friction is the
Angle between normal reaction and the resultant of normal reaction and the 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
Center of percussion is
The point of C.G.
The point of metacenter
The point of application of the resultant of all the forces tending to cause a body to rotate about a certain axis
Point of suspension
The motion of a particle round a fixed axis is
Translatory
Rotary
Circular
Translatory as well as rotary
The unit of angular velocity is
m/min
rad/s
Revolutions/min
Both (B) and (C)
The matter contained in a body, is called
Impulsive force
Mass
Weight
Momentum
Tangent of angle of friction is equal to
Kinetic friction
Limiting friction
Angle of repose
Coefficient of friction
The range of a projectile is maximum, when the angle of projection is
30°
45°
60°
90°