A uniform rod of mass 20 kg and length 5 m leans against a smooth vertical wall making an angle of $60^{\circ}$ with it. The other end rests on a rough horizontal floor. The friction force that the floor exerts on the rod is (Take $g=10 \mathrm{~m} / \mathrm{s}^2$)

The Sun rotates around its centre once in 27 days. What will be the period of revolution if the Sun were to expand to twice its present radius without any external influence? Assume the Sun to be a sphere of uniform density.

A sphere of radius $R$ is cut from a larger solid sphere of radius $2 R$ as shown in the figure. The ratio of the moment of inertia of the smaller sphere to that of the rest part of the sphere about the $Y$-axis is:

The radius of gyration of a solid sphere of mass $$5 \mathrm{~kg}$$ about $$X Y$$ is $$5 \mathrm{~m}$$ as shown in figure. The radius of the sphere is $$\frac{5 x}{\sqrt{7}} \mathrm{~m}$$, then the value of $x$ is:

A bob is whirled in a horizontal plane by means of a string with an initial speed of $$\omega \mathrm{~rpm}$$. The tension in the string is $$T$$. If speed becomes $$2 \omega$$ while keeping the same radius, the tension in the string becomes:

The moment of inertia of a thin rod about an axis passing through its mid point and perpendicular to the rod is $$2400 \mathrm{~g} \mathrm{~cm}^2$$. The length of the $$400 \mathrm{~g}$$ rod is nearly:

A wheel of a bullock cart is rolling on a level road as shown in the figure below. If its linear speed is $$v$$ in the direction shown, which one of the following options is correct ($$P$$ and $$Q$$ are any highest and lowest points on the wheel, respectively)?

A constant torque of $$100 \mathrm{~N} \mathrm{~m}$$ turns a wheel of moment of inertia $$300 \mathrm{~kg} \mathrm{~m}^2$$ about an axis passing through its centre. Starting from rest, its angular velocity after $$3 \mathrm{~s}$$ is :-

The ratio of radius of gyration of a solid sphere of mass $$M$$ and radius $$R$$ about its own axis to the radius of gyration of the thin hollow sphere of same mass and radius about its axis is :-

The angular acceleration of a body, moving along the circumference of a circle, is :

An energy of 484 J is spent in increasing the speed of a flywheel from 60 rpm to 360 rpm. The moment of inertia of the flywheel is :

The angular speed of a fly wheel moving with uniform angular acceleration changes from 1200 rpm to 3120 rpm in 16 seconds. The angular acceleration in rad/s² is

The ratio of the radius of gyration of a thin uniform disc about an axis passing through its centre and normal to its plane to the radius of gyration of the disc about its diameter is