Question

Select the correct choice(s)

• A. The gravitational field inside a spherical cavity within a spherical planet must be non zero and uniform.
• B. When a body is projected horizontally at an appreciable large height above the earth, with a velocity less than orbital velocity, it will fall to the earth along a parabolic path
• C. A body of zero total mechanical energy placed in a gravitational field will escape the field
• D. Earth's satellite must be in the equatorial plane.

Answer 1

The correct option is C A body of zero total mechanical energy placed in a gravitational field will escape the field

Gravitational field is a conservative field, total mechanical energy is conserved.

$U+K=0$
$\frac{1}{2}m{v}^2-\frac{GMm}{r}=0$
$v=\sqrt{\frac{2GM}{r}}$

Here as $v$ is equal to escape velocity,

Thus the body escapes to infinity.