We can add motors to our machines and learn how power or speed can be varied depending on the problem we are trying to solve.

• Learning about the gearing between the drive shaft and the load by towing a heavy load up a slope (an inclined plane!): here  (And we improved the tow hitch to prevent wheelies and loss of grip (traction).)

Base case with 1:1 gearing between drive and load

• Learning about gear ratios in a two speed gearbox: here with the Gear Racer, and in the follow-on lesson : turning revolutions into gear ratios.

Hand crank to help us determine gear ratios on the Gear Racer