The correct answer is Newton's 1st law of motion. Explanation & Key Takeaways: • The branch of a tree is shaken violently; the leaves fall due to Newton's 1st law of motion. • Due to the phenomenon of the law of inertia, the leaves try to be at rest when a tree is shaken, but the branch and trunk are in motion which causes the leaves to fall from its branch. • Newton's 1st law of motion states that a body is at rest; it will remain at rest unless it is acted upon by some external forces. Important Notes: • Newton’s 2nd law states that the acceleration of an object as produced by a net force is directly proportional to the magnitude of the net force, in the same direction as the net force, and inversely proportional to the mass of the object. • The Newton’s 3rd law states that for every action there is an equal and opposite reaction. Related Concepts: • The joule’s first law shows the relationship between heat produced by flowing electric current through a conductor. \(Q = I^2 R T\) • Joule's second law states that the internal energy of an ideal gas is independent of its volume and pressure, depending only on its temperature.