[quickthrowman]

> Gears multiply (increase or decrease) power from the engine depending on the gear you've selected.

Gears change how many times the wheels turn for every engine revolution.

Engine power is the product of angular velocity (rpm) and torque.

Gears are tangentially related to engine power output since they allow a user to select how fast the engine is spinning, but an engine outputs the same amount of power at a specific RPM regardless of what gear the transmission is in. 1800 RPM in 1st gear and 5th gear will generate the same amount of kW (or HP, if you prefer)

[tsujp]

Understood, but in this (hypothetical) example his mother probably doesn't know exactly what angular velocity or torque are, so making things even simpler with a laymans "power" serves to get the point across.

One could include torque in the explanation to which the follow-up is probably "what's torque?".

The simpler one goes for that initial understanding, in most cases, the less technically correct one is; by design that helps the newbie learn and build up to a more technically correct understanding later on.