The minimum force required to slide a body of weight W on a rough horizontal plane is
W sinθ
W cosθ
W tanθ
None of these
Correct Answer :
C. W tanθ
Related Questions
In ideal machines
Mechanical advantage is greater than velocity ratio
Mechanical advantage is equal to velocity ratio
Mechanical advantage is less than velocity ratio
Mechanical advantage is unity
The process of finding out the resultant force is called __________ of forces.
Composition
Resolution
Decomposition
None of these
The resultant of two forces P and Q (such that P > Q) acting along the same straight line, but in opposite direction, is given by
P + Q
P - Q
P / Q
Q / P
Which of the following is not the unit of energy?
kg m
kcal
Watt
Watt hours
The forces which meet at one point, but their lines of action __________ on the same plane, are Known as non-coplanar concurrent forces.
Lie
Do not lie
Either A or B
None of these
A framed structure is imperfect, if the numbers of members are __________ (2j - 3).
Equal to
Less than
Greater than
Either (B) or (C)
When a rigid body is suspended vertically, and it oscillates with a small amplitude under the action of the force of gravity, the body is known as
Simple pendulum
Compound pendulum
Torsional pendulum
Second's pendulum
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
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
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 coefficient of friction depends upon
Nature of surfaces
Area of contact
Shape of the surfaces
All of the above
A heavy string attached at two ends at same horizontal level and when central dip is very small approaches the following curve
Circular arc
Parabola
Hyperbola
Elliptical
If the masses of both the bodies, as shown in the below figure, are reduced to 50 percent, then tension in the string will be 
Same
Half
Double
None of these
A smooth cylinder lying on its convex surface remains in __________ equilibrium.
Stable
Unstable
Neutral
None 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
Which of the following is not a scalar quantity?
Mass
Volume
Density
Acceleration
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
Moment of inertia is the
Second moment of force
Second moment of area
Second moment of mass
All of these
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
Centre of gravity of a thin hollow cone lies on the axis at a height of
One-fourth of the total height above base
One-third of the total height above base
One-half of the total height above base
Three-eighth of the total height above the base
Pick up the incorrect statement from the following:
The C.G. of a circle is at its centre
The C.G. of a triangle is at the intersection of its medians
The C.G. of a rectangle is at the intersection of its diagonals
The C.G. of a semicircle is at a distance of r/2 from the centre
The centre of gravity of a semi-circle lies at a distance of __________ from its base measured along the vertical radius.
3r/ 8
4r/ 3π
8r/3
3r/4π
The forces, which meet at one point and their lines of action also lie on the same plane, are known as
Coplanar concurrent forces
Coplanar non-concurrent forces
Non-coplanar concurrent forces
Non-coplanar non-concurrent forces
The ratio of static friction to dynamic friction is always
Equal to one
Less than one
Greater than one
None of these
The moment of a force
Is the turning effect produced by a force, on the body, on which it acts
Is equal to the product of force acting on the body and the perpendicular distance of a point and the line of action of the force
Is equal to twice the area of the triangle, whose base is the line representing the force and whose vertex is the point, about which the moment is taken
All of the above
The centre of percussion of a solid cylinder of radius r resting on a horizontal plane will be
r/2
2r/3
r/A
3r/2
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
If the body falls freely under gravity, then the gravitational acceleration is taken as
+8.9 m/s2
-8.9 m/s2
+9.8 m/s2
-9.8 m/s2
The Cartesian equation of trajectory is (where u = Velocity of projection, α = Angle of projection, and x, y = Co-ordinates of any point on the trajectory after t seconds.)
y = (gx²/2u² cos²α) + x. tanα
y = (gx²/2u² cos²α) - x. tanα
y = x. tanα - (gx²/2u² cos²α)
y = x. tanα + (gx²/2u² cos²α)
Which of the following are vector quantities?
Linear displacement
Linear velocity
Linear acceleration
All of these