A student made the following observations about astronomical bodies. Observation 1: Mars reverses its direction of motion in the night's sky.
Observation 2: The stars move across the sky.

Which observation(s) can be explained using the heliocentric model but not the geocentric model?

(A)Only observation 1
(B) Only observation 2
(C) Both observation 1 and observation 2
(D) Neither observation 1 nor observation 2

Astone is thrown with a speed v0 and returns to earth, as the drawing shows. ignore friction and air resistance, and consider the initial and final locations of the stone. which one of the following correctly describes the change δpe in the gravitational potential energy and the change δke in the kinetic energy of the stone as it moves from its initial to its final location? options a.δpe = 0 j and δke = 0 j b.δpe is positive and δke is negative c.δpe = 0 j and δke is positive d.δpe is negative and δke is positive e.δpe = 0 j and δke is negative