A ball of mass $$0.2 \mathrm{~kg}$$ is thrown vertically down from a height of $$10 \mathrm{~m}$$. It collides with the floor and loses $$50 \%$$ of its energy and then rises back to the same height. The value of its initial velocity is
The moment of inertia of a rigid body about an axis
Seven identical discs are arranged in a planar pattern, so as to touch each other as shown in the figure. Each disc has mass $$m$$ radius $$R$$. What is the moment of inertia of system of six discs about an axis passing through the centre of central disc and normal to plane of all discs?
The true length of a wire is $$3.678 \mathrm{~cm}$$. When the length of this wire is measured using instrument $$A$$, the length of the wire is $$3.5 \mathrm{~cm}$$. When the length of the wire is measured using instrument $$B$$, it is found to have length $$3.38 \mathrm{~cm}$$. Then, the