A ship of mass 3x 107 kg initially at rest, is pulled by a force of 5x 104 N through a distance of 3m. Assuming that the resistance due to water is negligible, the speed of the ship is
1.5m/sec.
60m/sec.
0.1m/sec.
5m/sec.
A block of mass 0.1 is held against a wall applying a horizontal force of 5 N on the block. If the coefficient of friction between the block and the wall is 0.5 the magnitude of the frictional force acting on the block is:
2.5 N
0.98 N
4.9 N
0.49 N
A particle moves in the X-Y plane under the influence of a force such that its linear momentum is p(t)=A
[ î cos(kt)-jsin(kt), where A and K are constants. The angle between the force and the momentum is
0o
30o
45o
90o
A reference frame attached to the earth
Is an inertial frame by definition
Cannot be an inertial frame because the earth is revolving round the sun.
Is an inertial frame because Newton’s laws are applicable in this frame.
Cannot be an inertial frame because the earth is rotating about its own axis.
A body is moved along a straight line by a machine delivering constant power. The distance moved by the body in time t is proportional to
t1/2
t3/4
t3/2
t2
A force F= -K (yî+xj) (where k is a positive constant) acts on a particle moving in the xy plane. Starting from the origin, the particle is taken along the positive x axis to the point (a,0), and then parallel to the y axis to the point (a,a), The total work done by the force F on the particle is
-2Ka2
2Ka2
-Ka2
Ka2
A uniform chain of length L and mass M is lying on a smooth table and one third of its length is hanging vertically down over the edge of the table. If g is acceleration due to gravity, the work required to pull the hanging part on to the table is the work required to pull hanging part on to the table is
MgL
MgL/3
MgL/9
MgL/18
A particle is acted upon by a force of constant magnitude which is always perpendicular to the velocity of the particle. The motion of the particle takes place in a plane. It follows that:
Its velocity is constant
Its acceleration is constant
Its kinetic energy is constant
It moves in a circular path.
If a machine is lubricated with oil
The mechanical advantage of the machine increase
The mechanical efficiency of the machine increases
Both its mechanical advantage and efficiency increase
Its efficiency increases, but its mechanical advantage decreases.
a spring of force-constant k is cut into two pieces such that one piece is double the length of the other. Then the long piece will have a force-constant of
(2/3)k
(3/2)k
3 k
6 k
A wind-powered generator converts wind energy into electrical energy. Assume that the generator converts a fixed fraction of the wind energy intercepted by its blades into electrical energy. For wind speed V, the electrical power output will be proportional to
V
V2
V3
V4
A body is moved along a straight line by a machine delivering constant power. The distance moved by the body in time t is proportional to
t1/2
t3/4
t3/2
t2
A force F= -K (yî+xj) (where k is a positive constant) acts on a particle moving in the xy plane. Starting from the origin, the particle is taken along the positive x axis to the point (a,0), and then parallel to the y axis to the point (a,a), The total work done by the force F on the particle is
-2Ka2
2Ka2
-Ka2
Ka2
A uniform chain of length L and mass M is lying on a smooth table and one third of its length is hanging vertically down over the edge of the table. If g is acceleration due to gravity, the work required to pull the hanging part on to the table is the work required to pull hanging part on to the table is
MgL
MgL/3
MgL/9
MgL/18