Release a hoop, a solid disc, a solid sphere, a hollow sphere and a frictionless sliding block from the same height. Which one reaches the bottom first, and which comes last? Does it matter how heavy they are, or how big? Make your prediction, then press Play.
Why. They all arrive with the same total kinetic energy, but the rollers have to put some of it into spinning, so they arrive slower. Which one wins depends only on how its mass is spread out from the axis, not on how heavy it is or how big.
What to try. Change the mass, then the radius: the order never changes, and neither do the finish times. That is the surprise, and it is worth predicting before you drag the slider. Then look at the energy bars: the hoop puts half its energy into rotation, the sphere only two sevenths, and the sliding block none at all, which is exactly the order they finish in. Finally raise the ramp angle past the point where the friction needed exceeds what a real surface can supply; the table flags any object that would start to slip. After the finish line each object carries on along a level runout at the speed it reached, so the gaps you see at the end are the race result.
Units: meters and seconds, g = 9.8 m/s². Each object rolls without slipping from rest, with no rolling resistance or air drag; the block slides on a frictionless ramp and along a frictionless runout, so nothing slows down after the finish line. Acceleration is a = g sin θ / (1 + k), where I = kmR² defines the shape factor k: 1 for a hoop, ½ for a disc, ⅖ for a solid sphere, ⅔ for a thin hollow sphere, 0 for the sliding block. Mass and radius cancel out of a entirely.