Question

The Earth moving round the Sun in a circular orbit is acted upon by a force.

1. Name the force acting on the Earth.

2. Obtain a mathematical expression for the force.

3. What is the work done by the force?

Answer 1

1. Centripetal force

2. F_e = ma
F_c = m \(\frac{V^2}{r}\)

3. zero. (Displacement is always perpendicular to centripetal force).