Procedure
This demonstration includes two carts racing on a roller coaster track that with no added mass. The objective is to see which of the two carts will reach the end of the track first. This is one of the various practical experiments you can try on a roller coaster.
Which cart will finish first?
(Loop path or Straight path)
Materials
This link includes the materials and instructions on how to assemble the track.
The Physics Behind It
The cart on the track with a loop finished first because of its Rotational Kinetic Energy(RKE). The more RKE an object in motion has the faster it will go. It consists of the moment of inertia(I) and angular velocity(w).
Therefore...
RKE=1/2(Iw2)
where
Moment of Inertia = I=mr2
and
Angular Speed=w=Δangle/ Δtime
Angular displacement/change in time.