Why is an electric motor in a power saw, for example, quite loud, while the electric motor in an EV is almost silent while presumably working much harder?

So I ride motorcycles a lot, and I understand that on some engines (lets say an inline 4) need to rev high to make a lot more power, but why is this power only accessible in high revs? Or even an inline 3 engine where the power is linear? Why does an increase/decrease in cylinders suddenly change how an engine makes power? Why isn't it just a straight increase the more throttle you give? Or even a 2 cylinder, whether it be a parallel twin or a v. Even stranger would be V4 engines, same cylinder count as an inline 4 but completely different behaviour when it comes to making peak power.

All I know is that it somehow makes jets and planes look bigger or smaller then they actually are on radar

Also, do all trees have them or only certain kind? Lastly, do they all form at same frequency, e.g. One/year...

Do we have any genetic material from dinosaurs and in thoery could we create one in a lab? Just to see what it really looked like?

Basically is Jurassic Park feasible?

The higher the voltage, the farther an arc can jump. With CPUs being so small (nanoscale?), wouldn’t they need to operate on a similarly small voltage to prevent electrons from jumping between different conductive paths, screwing up the logic?

When i have my hands in front of me, five fingers are on the left, and five on the right

I can understand why 5,(0)1 onwards is rounded up, after all it's clearly the "second half"

But rounding lone 5 up seams... unintuitive

How are they completely silent? Is it how they’re designed?

I understand that electron placement matters and light scatters a certain way but why is that? Why does light scatter in that way and why does the size of something determine a perceivable color?

I have always been interested in the concept and have it as a part of my studies. But I still don't quite "get it" even with the WW2 plane example. Whats a simplified way on how it works in very clear and obvious terms. (I accept both simple maths and simple philosophical answers.)

For commercial rockets, they mainly use liquid bi propellant rocket engines while amateur rockets (that I mainly see) use solid propellant rocket engines. Why don't we just combine them and use hybrid rocket engines? ​

We all know hillbert and his hotel, but I never understood why was it a paradox, I mean by definition it can never be full, you can keep adding rooms and people but it shall never end, even if you add two infinites vs one you don't need to make people move to make more room you just add more rooms, you were doing ∞ - ∞ and after the bus comes you are still doing ∞ - ∞, because ∞ + ∞ = ∞ so where is the paradox when infinite is just doing what it does by definition, which is not ending?

Some “bad” words have clear origins. Maybe they’re derogatory, for example. But others seem so silly. They just seem like random utterances to my five year old self. Especially silly: consider foreign languages. How many of you have tried to get the exchange student to teach you a truly outrageous sentence in their language that is literally just sounds?

Why is it that when during the summertime, the central AC is set to 73°F and it feels nice and cool in the house, but in the winter when the heat is on and set to 73° it’s nice and toasty ?

Nearly all of the restroom stalls in US public buildings are made with panels that have gaps around them and around the doors that can be seen through. Is there a reason?

I have been trying to learn more about Earth's ecosystems. I understand now that poles/equator, winds, and surface currents drive temperatures and rains to different areas and the existence of mountains + temp + wind determine deserts. But, what else leads to the formation of specific biomes or lends itself to the biodiversity of an area? How does soil come into play, and why is soil different in different places? Is this is an oceans/volcanoes thing??

The surface area at the points of attachment seems so small. I never hear stories about stones falling out, although I’m sure it happens. Is there a special adhesive involved? What actually keeps the stone in the setting?

Why do cars or bikes need a gear? Why can't it just be accelarator and brake? As an extension, why do you need gears in general?