Let's see if anyone can figure this out

Why do you have to "put your two cents in"... but it's only a "penny for your thoughts"? Where's that extra penny going?

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