S ekedi high RPM set wenawa.. pallam waladi S dan yaddi dangerous.
So what happens when you go downhill is:
Gravity does all the work while the engine does nothing. Gravity spins the wheels, so the car keeps moving even though the engine isn’t actively pushing the car.
But the wheels are connected to the engine through the gearbox.
Gears S and B are the lowest gears available. Think of them like 2nd and 1st gears in a manual transmission, S = 2nd, B = 1st
In lower gears the engine has to spin faster to keep up with the wheels. For example in gear S, imagine the engine needs to spin twice for every spin of the wheel. In gear B, imagine the engine has to spin 4 times per 1 wheel spin.
So in gear S:
Gravity has to spin the wheels + spin the engine 2 times (2 RPM).
In gear B:
Gravity has to spin the wheels + spin the engine 4 times (4 RPM).
Basically, the lower the gear the more resistance gravity faces because it's now trying to spin the wheels while at the same time trying to spin the engine faster.
Gravity has to work harder and harder to move your car so the speed goes down even without you applying the brake.
So in the end while going downhill in B/S:
More RPM = The car slows down even further because the engine is not doing anything though it's spinning at higher RPMs, the gravity is the force that does everything downhill.
Capiche?