Two identical satellites are at the heights $R$ and $7R$ from the earth’s surface. Then which of the following statement is incorrect: ($R=$Radius of the earth)

Spaceman Fred's spaceship (which has negligible mass) is in an elliptical orbit about Planet Bob. The minimum distance between the spaceship and the planet is $\mathrm{R}$; the maximum distance between the spaceship and the planet is $2\mathrm{R}$. At the point of maximum distance, Spaceman Fred is traveling at speed $v_0.$ He then fires his thrusters so that he enters a circular orbit of radius $2\mathrm{R}$. What is his new speed?

Assuming potential energy '$U$' at ground level to be zero.

All objects are made up of same material:-

$U_P=$Potential energy of solid sphere

$U_Q=$Potential energy of solid cube

$U_R=$Potential energy of solid cone

$U_S=$Potential energy of solid cylinder

Two concentric shells of masses ${\mathrm{M}}_1$ and ${\mathrm{M}}_2$ are having radii ${\mathrm{r}}_1$ and ${\mathrm{r}}_2$. Which of the following given below is the right expression for the gravitational field at a distance r is