If the angular distance, 0 = 2t3 - 3t², the angular acceleration at t = 1 sec. is
1 rad/sec²
4 rad/sec²
6 rad/sec²
12 rad/sec²
Correct Answer :
C. 6 rad/sec²
Related Questions
For a body moving with simple harmonic motion, the number of cycles per second, is known as its
Oscillation
Amplitude
Periodic time
Frequency
For a simple pendulum, time period for a beat, is
π √(l/g)
π √(2l/g)
π √(g/2l)
π √(l/2g)
If the gravitational acceleration at any place is doubled, the weight of a body, will
Be reduced to half
Be doubled
Not be affected
None of these
The maximum displacement of a particle executing S.H.M. corresponds to
Zero potential energy and maximum kinetic energy
Zero kinetic energy and maximum potential energy
Maximum kinetic energy and maximum potential energy
Minimum kinetic energy and minimum potential energy
A shell travelling with a horizontal velocity of 100 m/sec explodes and splits into two parts, one of mass 10 kg and the other of 15 kg. The 15 kg mass drops vertically downward with initial velocity of 100 m/sec and the 10 kg mass begins to travel at an angle to the horizontal of tan1 x, where x is
3/4
4/5
5/3
3/5
The vertical reaction at the support A of the structure shown in below figure, is 
1 t
2 t
3 t
3.5 t
If two forces of 3 kg and 4 kg act at right angles to each other, their resultant force will be equal to
7 kg
1 kg
5 kg
None of these
A projectile is fired at an angle θ to the vertical. Its horizontal range will be maximum when θ is
0°
30°
45°
90°
One end of an elastic string of natural length / and modulus X is kept fixed while to the other end is attached a particle of mass m which is hanging freely under gravity. The particle is pulled down vertically through a distance x, held at rest and then released. The motion is
A simple harmonic motion
A rectilinear motion with constant speed
A damped oscillatory motion
None of the above
A system of coplanar forces is in equilibrium when
Force polygon closes
Funicular polygon closes
Both force polygon and funicular polygon close
All the forces are concurrent
If the angle between the applied force and the direction of motion of a body, is between 90° and 180°, the work done, is called
Virtual work
Imaginary work
Zero work
Negative work
The resultant of two forces P and Q acting at an angle θ, is
P2 + Q2 + 2P sin θ
P2 + Q2 + 2PQ cos θ
P2 + Q2 + 2PQ tan θ
√(P2 + Q2 + 2PQ cos θ)
For a non-concurrent force system to be in equilibrium
Only the closure of force polygon is sufficient
Only the closure of funicular polygon is sufficient
Both force polygon and funicular polygon must close
None of the above
Time period and length of a seconds pendulum respectively are
1 sec and 99.4 cm
1 sec and 92.7 cm
2 sec and 99.4 cm
2 sec and 92.7 cm
Joule is the unit of
Power
Impulse
Work
Momentum
Which one of the following statements is true?
The tangent of the angle of friction is equal to coefficient of friction
The angle of repose is equal to angle of friction
The tangent of the angle of repose is equal to coefficient of friction
All the above
The mechanical advantage of an ideal machine is 100. For moving the local through 2 m, the effort moves through
0.02 m
2 m
2.5 m
20 m
If α and u are the angle of projection and initial velocity of a projectile respectively, the horizontal range of the projectile, is
u² sin α/g
u² sin² α/g
u² sin α/2g
u² sin² α/2g
If a projectile is fired with an initial velocity of 10 m/sec at an angle of 60° to the horizontal, its horizontal and vertical velocity at the highest point of trajectory are
0 and 5 m/sec
5 m/sec and 0
5√3 m/sec and 0
5 and 5√3 m/sec
A ball is dropped from a height of 16 m on a horizontal floor. If it rebounds to a height of 9 m after striking the floor, the coefficient of restitution between ball and floor is
1/4
2/3
3/4
4/3
If two equal forces of magnitude P act at an angle θ, their resultant, will be
P cos θ/2
2P sin θ/2
P tan θ/2
2P cos θ/2
A bullet weighing 200 g is fired horizontally with a velocity of 25 m/sec from a gun carried on a carriage which together with the gun weighs 100 kg. The velocity of recoil of the gun, will be
0.01 m/sec
0.05 m/sec
1.00 m/sec
1.5 m/see
A rod AB carries three loads of 30 N, 70 N and 100 N at distances of 20 mm, 90 mm and 150 mm respectively from A. Neglecting the weight of the rod, the point at which the rod will balance is
109.5 mm from A
119.5 mm from A
125.5 mm from A
132.5 mm from A
In simple harmonic motion, acceleration of a particle is proportional to
Rate of change of velocity
Displacement
Velocity
Direction
A particle is dropped from a height of 3 m on a horizontal floor, which has a coefficient of restitution with the ball of 1/2. The height to which the ball will rebound after striking the floor is
0.5 m
0.75 m
1.0 m
1.5 m
Pick up the incorrect statement from the following. In case of suspension bridge due to rise in temperature,
Dip of the cable increases
Length of the cable increases
Dip of the cable decreases
None of these
Power developed by a torque, is
2πNT kg m/min
2πNT/4500 h.p
2πNT /60 watts
All the above
A trolley wire weighs 1 kg per metre length. The ends of the wire are attached to two poles 20 m apart. If the horizontal tension is 1000 kg, the central dip of the cable is
2 cm
3 cm
4 cm
5 cm
Newtons Law of Motion is:
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
All the above
To attain the synchronous orbit, the launch of a satellite, is done from a place
On equator
On 30° latitude
On 45° latitude
On the poles