The velocity of a body on reaching the ground from a height h, is
2.√(gh)
√(gh)
√(2gh)
2g.√h
Correct Answer :
C. √(2gh)
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 maximum height of a projectile on a horizontal plane, is
u² sin²α/2g
u² cos²α/2g
u² sin²α/g
u² cos²α/g
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
An ideal machine is one whose efficiency is
Between 60 and 70 %
Between 70 and 80 %
Between 80 and 90 %
100 %
The velocity ratio for the third system of pulleys is
n
n²
2n
2n - 1
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
The resultant of two forces P and Q acting at an angle θ is
√(P² + Q² + 2PQ sinθ)
√(P² + Q² + 2PQ cosθ)
√(P² + Q² - 2PQ cosθ)
√(P² + Q² - 2PQ tanθ)
The moment of inertia of a solid cone of mass m and base radius r about its vertical axis is
3mr2/5
3mr2/10
2mr2/5
4mr2/5
If three forces acting in different planes can be represented by a triangle, these will be in
Non-equilibrium
Partial equilibrium
Full equilibrium
Unpredictable
When trying to turn a key into a lock, following is applied
Coplanar force
Non-coplanar forces
Moment
Couple
The force, by which the body is attracted, towards the centre of the earth, is called
Impulsive force
Mass
Weight
Momentum
The centre of percussion is below the centre of gravity of the body and is at a distance equal to
h/kG
h2/kG
kG2/h
h × kG
The C.G. of a solid hemisphere lies on the central radius 3r
At distance from the plane base 3r
At distance from the plane base 3r
At distance from the plane base 3r
At distance from the plane base
The frequency of oscillation of a compound pendulum is (where kG = Radius of gyration about the centroidal axis, and h = Distance between the point of suspension and C.G. of the body.)
2π. √(gh/kG² + h²)
2π. √(kG² + h²/gh)
1/2π. √(gh/kG² + h²)
1/2π. √(kG² + h²/gh)
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 
In the shaded area
In the hole
At O
None of these
The friction experienced by a body, when at rest, is known as
Static friction
Dynamic friction
Limiting friction
Coefficient of friction
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
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
A framed structure is imperfect, if the numbers of members are __________ (2j - 3).
Equal to
Less than
Greater than
Either (B) or (C)
Tension in the cable supporting a lift is more when the lift is moving __________ with an acceleration.
Upwards
Downwards
Horizontal
None of these
The length of a second's pendulum is
94.9 cm
99.4 cm
100 cm
101 cm
Moment of inertia of a hollow circular section, as shown in the below figure about X-axis, is 
π/16 (D² - d²)
π/16 (D³ - d³)
π/32 (D⁴ - d⁴)
π/64 (D⁴ - d⁴)
The amplitude is always __________ radius of the circle.
Equal to
Less than
Greater than
None of these
When a body of mass m attains a velocity v from rest in time t, then the kinetic energy of translation is
mv2
mgv2
0.5 mv2
0.5 mgv2
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 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
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
Area of the triangle
Twice the area of the triangle
Half the area of the triangle
None of these
According to Newton's first law of motion,
Everybody continues in its state of rest or of uniform motion, in a straight line, unless it is acted upon by some external force
The rate of change of momentum is directly proportional to the impressed force, and takes place in the same direction, in which the force acts
To every action, there is always an equal and opposite reaction
None of the above
Tangent of angle of friction is equal to
Kinetic friction
Limiting friction
Angle of repose
Coefficient of friction
The angle which an inclined plane makes with the horizontal when a body placed on it is about to move down is known as angle of
Friction
Limiting friction
Repose
Kinematic friction