The correct graph representing the variation of total energy $(E_t)$,kinetic energy $(E_k)$,and potential energy $(U)$ of a satellite with its distance $(r)$ from the centre of the Earth is:

$A$ spacecraft which is moving with a speed $u$ relative to the earth in the $x$-direction,enters the gravitational field of a much more massive planet which is moving with a speed $3u$ in the negative $x$-direction. The spacecraft exits following the trajectory as shown below. The speed of the spacecraft with respect to the earth a long time after it has escaped the planet's gravity is given by

Mention the cause of an earthquake.

$A$ body projected vertically from the earth reaches a height equal to earth's radius before returning to the earth. The power exerted by the gravitational force is greatest

During the motion of a planet from perihelion to aphelion,the work done by the gravitational force of the sun on it is ...........

For a satellite to orbit around the earth,which of the following must be true?