Which one of the following is not a contact force ?
Viscous force
Air resistance
Magnetic force
Buoyant force
A force N acting on a body maintains its velocity at ms-1. The power exerted is
4 W
5 W
2 W
8 W
A.
4 W
Identify the false' statement from the following
Work-energy theorem is not independent of Newton's second law
Work-energy theorem holds in all inertial frames
Work done by friction over a closed path is zero
No potential energy can be associated with friction
Three bricks each of length L and mass M are arranged as shown from the wall. The distance of the centre of mass of the system from the wall is
L/4
L/2
(3/2)L
(11/12)L
A fly wheel of moment of inertia 3 x 102 kg m2 is rotating with uniform angular speed of 4.6 rads-1. If a torque of 6.9 x 102 Nm retards the wheel, then the time in which the wheel comes to rest is
1.5 s
2 s
0.5 s
1 s
Moment of inertia of a ring of mass M and radius R about a tangent to the circle of the ring is
MR2
If the escape velocity of a planet is 3 times that of the earth and its radius is 4 times that of the earth, then the mass of the planet is (Mass of the earth = 6 x 1024 kg)
1.62 × 1022 Kg
0.72 × 1022 kg
2.16 × 1026 kg
1.22 × 1022 kg
The total energy of a circularly orbiting satellite is
twice the kinetic energy of the satellite
half the kinetic energy of the satellite
half the potential energy of the satellite
equal to the potential energy of the satellite
If an earth satellite of mass m orbiting at a distance 2R from the centre of earth has to be transferred into the orbit of radius 3 R, the amount of energy required is (R = radius of earth)
mgR