1. The problem statement, all variables and given/known data The motions of a pendulum and a planet undergoing circular motion are compared a) describe a similarity in their motions b)describe a difference in their motion c) Outline a differance in the forces acting on the pendulum and the planet 2. Relevant equations 3. The attempt at a solution a) They both have a displacement of 0? b)one is circular, one is not? c)? I'm looking for a more thourough answer.