In what way does the mpg or kmpl number of a car depend on its speed? Is the advertised number based on average speed or a specific speed (say, 60 km/h)?
In: Engineering
Think about it like a bike on a flat road. When you start you’re probably on a gear that translates a lot of leg movement into not a lot of bike movement. As you get moving you’ll shift gears so you can increase bike speed without increasing your leg speed. As you progress you won’t really be working harder, more like just maintaining and slightly building on the momentum you’ve established. At a certain point, you’ll run out of gears and to go faster you’ll have to start pedaling faster expending more energy to increase your speed.
Cars are similar in that they shift gears to keep the engine spinning at a certain speed up until they’re in that top gear where the RPMs are low and speed is high. Then if you go faster increasing your RPMs without another gear to shift into, you’ll go faster but burn more fuel (and instead of building muscle, you’ll wear your engine out faster).
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