A projectile is fired at an angle θ to the vertical. Its horizontal range will be maximum when θ is
0°
30°
45°
60°
Correct Answer :
C. 45°
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
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
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.
When the lift is moving upwards with some acceleration, the pressure exerted by a man is __________ to its acceleration.
Directly proportional
Inversely proportional
Cube root
None of these
The acceleration of a particle moving with simple harmonic motion is __________ at the mean position.
Zero
Minimum
Maximum
None of these
When trying to turn a key into a lock, following is applied
Coplanar force
Non-coplanar forces
Moment
Couple
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
The moment of the force P about O as shown in the below figure is 
P × OA
P × OB
P × OC
P × AC
A block of mass 20 kg lying on a rough horizontal plane is connected by a light string passing over a smooth pulley to another mass 5 kg, which can move freely in the Vertical direction, as shown in the below figure. The tension in the string will __________ with the increase in coefficient of friction. 
Increase
Decrease
Not be effected
None of these
The resultant of the following three couples 20 kg force, 0.5 m arm, +ve sense 30 kg force, 1 m arm, -ve sense 40 kg force, 0.25 m arm, +ve sense having arm of 0.5 m will be
20 kg, -ve sense
20 kg, + ve sense
10 kg, + ve sense
10 kg, -ve sense
A pendulum which executes one beat per second is known as
Simple pendulum
Compound pendulum
Torsional pendulum
Second's pendulum
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 moment of inertia of a solid cylinder of mass m, radius r and length l about the longitudinal axis or polar axis is
mr2/2
mr2/4
mr2/6
mr2/8
The maximum height of a projectile on a horizontal plane, is
u² sin²α/2g
u² cos²α/2g
u² sin²α/g
u² cos²α/g
Moment of inertia of a triangular section of base (b) and height (h) about an axis passing through its C.G. and parallel to the base, is
bh3/4
bh3/8
bh3/12
bh3/36
When a body falls freely under gravitational force, it possesses __________ weight.
No
Minimum
Maximum
None of these
The unit of force in S.I. units is
kilogram
Newton
Watt
Dyne
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
A particle inside a hollow sphere of radius r, having coefficient of friction μ can rest up to height of
r/2
r/A
r/3
0.134 r
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
The force required to move the body up the plane will be minimum if it makes an angle with the inclined plane __________ the angle of friction.
Equal to
Less than
Greater than
None of these
The coefficient of friction depends on
Area of contact
Shape of surfaces
Strength of surfaces
Nature of surface
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 three forces of 100 N, 200 N and 300 N have their lines of action parallel to each other but act in the opposite directions. These forces are known as
Coplanar concurrent forces
Coplanar non-concurrent forces
Like parallel forces
Unlike parallel forces
The force, by which the body is attracted, towards the centre of the earth, is called
Impulsive force
Mass
Weight
Momentum
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
The acceleration of a body sliding down an inclined surface is
g sinθ
g cosθ
g tanθ
None of these
The acceleration of a particle moving with simple harmonic motion, at any instant is given by
ω.y
ω2.y
ω2/y
ω3.y
The range of a projectile is maximum, when the angle of projection is
30°
45°
60°
90°
The moment of inertia of a thin spherical shell of mass m and radius r, about its diameter is
mr2/3
2mr2/3
2mr2/5
3mr2/5