1. A ball rolls down a 3m-high smooth ramp. What speed does it have at the bottom?
2. In an otherwise empty universe, two planets of mass 1025 kg are 1012 m apart. What are their speeds when they collide?
(Not too sure about this one. Please check.)
3. What is the least work a 2000kg car must do to drive up a 100m hill?
4. How does the speed of a planet in an elliptical orbit change as it nears its star?
As it nears the star, it loses gravitational potential energy, and so gains kinetic energy, so its speed increases.