The amount of change in movement of an object is based on the mass of the object and the amount of force exerted.
This concept can be taught with Minecarts. Students can build three different tracks for Minecarts:
Track 1: Straight and flat (20 pieces of track)
Track 2: Uphill (20 pieces of track)
Track 3: Downhill (20 pieces of track)
Students can then discuss how the minecraft traveled differently on all three tracks and what forces may have been acting on the minecart to make it move the way it did.
The lesson can be extended by having students discuss the amount of track that would be needed to get to the same location for each type of track.
The students can also see what using the same three tracks would be like with a Minecart with Chest. There are actual physics at play based on the load in the Minecart. They could compare travel time between a Minecart, Minecart with Chest (empty), Minecart with Chest (half full), and Minecart with Chest (full). They could conduct time trials as well.