What is the minimum kinetic energy needed to launch a payload of mass m to an altitude that is one Earth radius, RE, above the surface of the Earth (the payload will then fall back to Earth)? (Note that ME is the mass of the Earth.)

Which of the following is a true statement about the acceleration ~a of the pendulum bob ~a is equal to the acceleration due to gravity. ~a is perpendicular to the bob’s trajectory. ~a is equal to the instantaneous rate of change in velocity. ~a is tangent to the bob’s trajectory.