A rock with a mass of $40\,\text{kg}$ is dropped from rest at a point $20\,\text{m}$ above the surface of a planet. When the rock reaches the planet’s surface, its kinetic energy is $32\,\text{kJ}$. The planet has no atmosphere. What is the weight of the rock on the surface of the planet?
- A$1.6\,\text{N}$
- B$390\,\text{N}$
- C$1.6\,\text{kN}$
- D$64\,\text{kN}$