3 ms·
> Brakes _do_ stop a car. Sure, from a lay perspective. Though I stop my car routinely without ever touching the brakes. Even my gas car does a non-trivial a
by rootusrootus 4y ago
> Brakes _do_ stop a car.
Sure, from a lay perspective. Though I stop my car routinely without ever touching the brakes. Even my gas car does a non-trivial amount of braking without using friction pads. But the point stands. Brakes don't touch the road, the tire does, so it matters not at all how you apply force to the wheel, from the perspective of the tire-to-road interface it's all the same.
If we want to have some fun with the physics, brake pads don't use dynamic friction to stop the car, either. Not most of the time, at least. Which is why they last as long as they do.
- mlindner 4y agoI was responding to the idea in the previous post that it was somehow that tires stop the cars rather than brakes or regenerative braking. > Brakes don't touch the road, the tire does, so it matters not at all how you apply force to the wheel, from the perspective of the tire-to-road interface it's all the same. This is not the case. Brakes (or regenerative braking) absorb the energy of motion into heat or stored chemical energy. The tires are not doing the stopping. > brake pads don't use dynamic friction to stop the car This is also incorrect. Brake pads are using almost completely dynamic friction to stop the car. From the perspective of the brake bads the tire is moving and from the perspective of the tire the brake pads are moving. There's no static friction involved there.