A system consists of three particles each of mass '$$m_1$$' placed at the corners of an equilateral triangle of side '$$\frac{\mathrm{L}}{3}$$', A particle of mass '$$\mathrm{m}_2$$' is placed at the mid point of any one side of the triangle. Due to the system of particles, the force acting on $$\mathrm{m}_2$$ is
The moment of inertia of a uniform square plate about an axis perpendicular to its plane and passing through the centre is $$\frac{\mathrm{Ma}^2}{6}$$, where '$$M$$' is the mass and '$$a$$' is the side of square plate. Moment of inertia of this plate about an axis perpendicular to its plane and passing through one of its corners is
Two lenses of power $$-15 \mathrm{D}$$ and $$+5 \mathrm{D}$$ are in contact with each other. The focal length of the combination is
A particle performing uniform circular motion of radius $$\frac{\pi}{2} \mathrm{~m}$$ makes '$$\mathrm{x}$$' revolutions in time '$$t$$'. Its tangential velocity is