A wheel starts from rest and spins with a constant angular acceleration. As time goes on the acceleration vector for a point on the rim
  • increases in magnitude and becomes more nearly radial
  • decreases in magnitude and becomes more nearly radial
  • increases in magnitude and becomes more nearly tangent to the rim
  • increases in magnitude but retains the same angle with the tangent to the rim
The following questions consists of two statements , Assertion and Reason. While answering these questions choose any of the following four responses Statement I : Two cylinder , one hollow (metal) and the other solid(wood) with the same mass and identical dimension are simultansouly allowed to roll without slipping down on a inclined plane from the same height. The hollow cylinder will reach the bottom of the inclined plane first Statement II: By the principle of conservation of energy ,the total kinetic energies of both the cylinders are identical when reach the bottom of the incline
  • If both statement I and reason are true but Statement II is not a correct explanation of statement I.
  • If statement I is false and Statement II is true
  • If statement I  is true and Statement II is false.
  • If both statement I and Statement II are true and the Statement II is correct explanation of statement I.
A uniform sold sphere rolls on the horizontal surface at 20 m/s.it then rolls up the incline of 30°.If friction losses are negligible what will be the value of h where sphere stops on the incline
  • 28.6 m
  • 30 m
  • 28 m
  • none of these
A mass is moving with constant velocity along a line parallel to x-axis  away from origin.its angular momentum with respect to origin is
  • remains constant
  • goes on decreasing
  • is zero
  • goes on increasing
An ice  skater spins with arms outstretch at 1.9 rev/s.Her moment of inertia at this time is 1.33 kgm2.She pulls  her arms to increase her rate of spin.Her moment of inertia after she pulls her arm is .48kgm2.What is her new rate of spinning
  • 4.7 rev/s
  • 5.26 rev/s
  • 4.0 rev/s
  • 5.2 rev/s
A wheel initially has an angular velocity of 18 rad/s. It has a constant angular acceleration of 2.0 rad/s2 and is slowing at first. What time elapses before its angular velocity is 18 rad/s in the direction opposite to its initial angular velocity?
  • 10 sec
  • 3 sec
  • 18 sec
  • 6 sec
A mass is whirled in a circular path with constant angular velocity and its angular momentum is L.If the string is now halve keeping the angular velocity same then angular momentum is
  • L
  • 2L
  • L/2
  • L/4
A cylinder of Mass M and radius R rolls down a incline plane of inclination $\theta$.Find the linear accleration of the cylinder
  • $\frac {2gcos \theta}{3}$
  • $gsin \theta$
  • $\frac {3gcos \theta}{2}$
  • $\frac {2gsin \theta}{3}$
For a wheel spinning with constant angular acceleration on an axis through its center, the ratio of the speed of a point on the rim to the speed of a point halfway between the center and the rim is:
  • 1/2
  • 4
  • 1/4
  • 2
A hoop of radius r and mass m rotating with an angular velocity $\omega _0$ is placed on a rough horizontal surface . The initial velocity of the center of the hoop is zero. What will be the velocity of the center of the hoop when it ceases to slip?
  • $r \omega _0$
  • $\frac {r \omega _0}{2}$
  • $\frac {r \omega _0}{3}$
  • $\frac {r \omega _0}{4}$
Two wheels are identical but wheel B is spinning with twice the angular speed of wheel A. The ratio of the magnitude of the radical acceleration of a point on the rim of B to the magnitude of the radial acceleration of a point on the rim of A is:
  • 1/2
  • 1/4
  • 2
  • 4
Moment of inertia of a uniform rod of length L and mass M about an axis passing through L/4 from one end and perpendicular to its length
  • 7ML2/48
  • 11ML2/48
  • ML2/12
  • 7ML2/36
Four Solid spheres each of diameter $\sqrt 5$ cm and mass .5 kg are placed with their centers at the corners of a square of side 4 cm. The moment of inertia of the system about the diagonal of the sphere is $N \times 10^{-4} \ kg-m^2$, then N is
  • 9
  • 8
  • 4
  • 5
A cylinder rolls up the incline plane reaches some height and then roll down without slipping through out this section.The direction of the frictional force acting on the cylinder are
  • down the incline while ascending and up the incline while descending
  • Up the incline while ascending and desending
  • down the incline while ascending and desending
  • Up the incline while ascending and down the incline while descending
One solid sphere X and another hollow sphere Y are of same mass and same outer radii. Their moment of inertia about their diameters are respectively Ix and Iy such that
  • Ix > Iy
  • Ix= Iy
  • Ix/Iy=Dx/Dy Where Dx and Dy are their densities.
  • Ix < Iy
0 h : 0 m : 1 s