How does one moving slowly cause the others to go faster and faster?
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If one gear has 10 teeth and the other has 100 teeth, then the small one turns 10 times for every 1 turn of the big one. The teeth are linked, so the rotation is counting teeth. You still need the power to turn the wheels, though.
Bicycles have mechanisms for changing the gear ratios, so you can move your legs at a comfortable speed even if you’re going slow or fast.
Think about this, the land 10 feet from the north pole only needs to travel like 60 feet when the earth does a full rotation… The land at the equator travels something like 28000 miles in that rotation. All part of the same mass, but one circular slice of the earth is small, one is big… All part of one solid thing, but traveling at different speeds. Not the exact same principle, but hope that gets you in the right thought process.
So let’s say you have something rotating a big gear at 1 rotation per minute, that gear has 100 teeth on it. It’s connected to a gear that’s 1/4 the size, so it has 25 teeth. Every one turn of the 100 teeth on the big gear is going to turn the smaller gear with 25 teeth 4 times, so whatever it’s spinning is going to be four times faster than what’s spinning the big gear
It’s just geometry. There’s probably a better explanation for this, but think of pizza sizes. You know instinctively that a 3 inch diameter pizza is tiny but a 6 inch diameter pizza is multiple times larger.
The same applies to gears. Gear chains are attached to their inner parts, so the energy to turn them 360 degrees is mostly the same whether they’re tiny or large. But the large ones are really huge and cover really large distances on every 360 revolution. The tiny ones cover almost no distance.
A wheel converts rotation at its axle into linear motion at a point along its circumference (the distance around the outside of a circle).
A bigger wheel has a greater circumference than a smaller wheel.
Gears are wheels whose edges touch. As gears turn, adjacent edges pass the point of contact at the same speed. The circumference of the smaller wheel is shorter, so a particular tooth it will come around to the point of contact again sooner than the corresponding tooth on the bigger gear.
Every time a particular tooth passes the point of contact, the gear has turned another full revolution. So the bigger gear (which has a larger circumference and more teeth) takes longer to compete a full revolution than a smaller gear with fewer teeth.
Gears have teeth to keep their relative rotation in perfect aligmment and to transfer torque from one gear to the next.
There is the rotational speed of a gear (Ex: 500 RPM) and the speed of cirumference (ex: 5 m/s)
2 gear with the same rotational speed, but different diameters will have different speeds at the circumference.
By meshing the gears, you are forcing these circumference speeds to be the same and therefore tje rotational speed will be different.
The teeth of meshing gears are always the same size, otherwhise they will not mesh correctly. Larger diameter gears therefore always have more teeth and the ratio between teeth will also determine the ratio between rotational speeds.
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