ratio
It depends on the ratio of the number of teeth on the two gears.
No, while one gear is turning the other the other gear should move the opposite direction. I learned this in robotics class.
Gears can change direction of rotational force from one axis to another. For example, a wind driven mill. The wind turns a shaft that is horizontal. That shaft turns a gear that is vertical, and the vertical gear meshes with a horizontal gear that turns a vertical shaft. Gears can change rotational speed. With a small gear meshed and turning a larger gear, the larger gear will have a slower RPM. Gears can change torque to increase or decrease available power. A small low force gear driving a larger gear will provide more rotational force.
it turns
It is the gear reduction that happens in the axle. With a 4.10 the pinion turns 4.1 times for every turn of the ring gear. The driveshaft is attached to the pinion and the ring gear turns the axle shafts, Which turn the wheels.
Number of rotation of the input shaft to turns of the ring gear. For example, a 3.55 gear ratio would mean the input shaft rotated 3.55 turns for each turn of the ring gear and axle shafts.
Turn the drive gear 1 complete turn, and count how many times the driven gear turns. For example, to figure out the rear end gear ratio if the drive shaft turns once and the rear turns 3 and a half times you have a 1:3.5 gear ratio. This means the rear wheels turn 3.5 times for each one turn of the drive shaft.
The speed of gear A can be calculated using the gear ratio. Since gear A has 10 teeth and gear B has 40 teeth, the gear ratio is 1:4. If gear B turns at 10 RPM, gear A will turn at 4 times that speed, which is 40 RPM.
It should be turned by a gear on the cam shaft
If they are the same, they will turn at the same speed.
A big gear turning a small gear means the small gear will spin faster, but weaker.