Topic: Gravity
Concepts: Gauss’s law for gravity, Kepler’s laws, Projectile motion

Solution:

• A) Not correct since a sphere can be replaced with a point mass anywhere outside of the sphere.
• B) Not correct since the ground only prevents the particle from continuing its orbit.
• C) Not correct since the particle is a bound object as it falls back to the planet.
• D) Not correct since Kepler’s laws don’t depend on the size of the orbits.
• E) Correct because the laws of projectile motion make the approximation that gravity is constant while it decreases inverse square with respect to distance.

Thus, the answer is E.