Four particles each of mass $m$ are placed at the vertices of a square of side $l.$ The potential energy of the system is

For a satellite moving in an orbit around the earth, the ratio of kinetic energy to potential energy is

Two planets have masses $M$ and $16\, M$ and their radii are $a$ and $2\, a$ respectively. The separation between the centres of the planets is $10\, a.$ A body of mass $m$ is fired from the surface of the larger planet towards the smaller planet along the line joining their centres. For the body to be able to reach at the surface of smaller planet, the minimum firing speed needed is

Figure shows the orbit of a planet $P$ round the sun $S.$ $AB$ and $CD$ are the minor and major axes of the ellipse.

If $U$ is the potential energy and $K$ kinetic energy then $|U| > |K|$ at

The gravitational potential energy of a body of mass $‘m’$ at the earth’s surface $ – mg{R_e}$. Its gravitational potential energy at a height ${R_e}$ from the earth’s surface will be (Here ${R_e}$ is the radius of the earth)