If a system has 475 kcal of work done to it, and releases 5.00 × 102 kj of heat into its surroundings, what is the change in internal energy of the system?

Which body is in equilibrium? (1) a satellite orbiting earth in a circular orbit (2) a ball falling freely toward the surface of earth (3) a car moving with a constant speed along a straight, level road (4) a projectile at the highest point in its trajectory