http://www.google.com/imgres?q=roll...art=0&ndsp=15&ved=1t:429,r:14,s:0&tx=39&ty=51 I had to design a rollercoaster that some what looks like this. And I have to figure out forces at the top and bottom of the loop. Can you tell me if i got this right?? The force of the top will be weight and normal force pointing down and bottom will have weight down and normal force up. Also, what does it mean to have force is zero at the top of the loop??? Can there be potential energy and kinetic energy at the loop?