Planes and cars have problems braking if brakes are too hot. F1 teams complain also if brakes are too cold. What’s the reason behind so much variance?
Also, I have noticed, that basically any vehicle have smaller deceleration when moving fast than when moving slow. From elementary school physics – when I apply some force onto surface, I should get some amount of friction, so I don’t know why it changes. It this also related to the temperature, or is there unrelated mechanism behind it?
In: Physics
So for your first point, the reason brakes become weaker if they’re too hot is that as materials get hotter they generally become softer which makes them worse as brakes. F1 brakes can reach temperatures as high as 1000C, and if you were to heat a regular steel brakes to that temperature it becomes so soft to be effectively useless (F1 cars and other high performance cars use variants of carbon brakes which work at higher temperatures).
For your second point, brakes convert the kinetic (movement) energy of the car into thermal (heat) energy. Brakes convert the energy at a fairly constant rate assuming they’re not too hot/cold. However kinetic energy is to the square of its speed, meaning an object travelling twice as fast will have 4 times the kinetic energy. So the brakes will have to get rid of 4 times the energy, meaning it will take 4 times as long, even if it’s only going twice the speed.
Latest Answers