Question

The work done by the Sun’s gravitational force on the Earth is ……… 

(a) Always zero 

(b) Always positive 

(c) Can be positive or negative 

(d) Always negative

Answer 1

(c) Can be positive or negative

Comments

What is the reason for this answer is correct

Answer 2

(c) Can be positive or negative 

The force exerting on the planet due to the gravity is always toward to sun. When potential energy decrease the work done by the gravity is positive when the potential energy of the planet has increased. then work done by the gravity is negative.