Science Buddies: "Ask an Expert"

My science teacher asked me to make a roller coaster to demonstrate Newtons three laws of physics. I have already planned my project and it's due in two days, and I have to present it! I had already decided that I will demonstrate his law that says for every action for there is an equal and opposite reaction force by putting a piece of wood at the end and letting m marble bounce off. The other two laws are the parts I'm having trouble with. Can anyone help me??

You can find a pretty good explanation of Newton's Laws [[here]]. The first law involves objects in motion staying in motion, and objects at rest staying at rest. How could you demonstrate an object continuing to move at (more or less) the same speed?

The Second Law essentially has to do with lighter objects moving more quickly when the same external force is applied. So could you demonstrate this by varying the force with which you push the marble (or rollercoaster car) at the beginning?