Comment on Physicists vs Normal People
Coreidan@lemmy.world 2 months ago
I don’t get it
Acceleration is change in velocity. When you press gas or break you can feel positive or negative Acceleration. When you turn the wheel you will feel Acceleration sideways.
Another analogy is force. F=ma. You feel a force if you accelerate, break or turn the wheel, so all three induce Acceleration as defined in physics.
Breaking doesn’t cause acceleration, it just causes damage.
So something slowing down is acceleration?
I still don’t get it. Surely the definition of acceleration is a lot more than just a change in velocity.
But I’m just a dumb ass so don’t listen to me.
Yeah, I get what you mean. So, “acceleration is how fast an object’s speed changes”. See, hitting the brakes or the gas are both acceleration, physics-wise. But not usually how we talk about it.
It’s easier to grasp when you’re doing the calculations.
You’re pretty smart to ask and dig deeper!
Slowing down is negative acceleration if that helps.
In common usage, “accelerate” means “go faster”.
In physics “accelerate” means “change of velocity over time”. It doesn’t just mean that the velocity increases, just that it changes.
In common usage “velocity” is the same thing as “speed”.
In physics “velocity” is “speed in a specific direction”. So, “80 km/h” isn’t a complete velocity statement. “80 km/h going west” is.
So, a car going at a speed of 80 km/h has a velocity of 80 km/h in the forward direction. Pressing the accelerator causes an acceleration in the forward direction, increasing the speed/velocity. Pressing the brake causes an acceleration in the backward direction, decreasing the speed/velocity. Turning the wheel causes an acceleration in the left/right direction. In this case, the speed might not change, but the velocity changes because the direction of travel changes.
If you imagine blowing on an air hockey puck it’s a bit easier to understand. There’s a fundamental rule in Physics that F = m × a, force is equal to mass times acceleration. Or, force divided by mass equals acceleration. If you blow on an air hockey puck, you exert a force on it, causing it to accelerate. If the air hockey puck is moving away from you, blowing on it will cause a forward acceleration increasing its velocity. If you blow on it as it’s coming towards you, you cause an acceleration backwards, decreasing its velocity. If you blow on it as it’s passing by you, you accelerate it sideways. In every case the same F=m × a equation applies, but sometimes the speed gets bigger, sometimes it gets smaller. The trickier one to calculate is when the force causes the direction of travel to change. Then instead of just needing an “x” variable you need “x” and “y”, or if you’re talking about velocity, vx and vy.
So, in a car, the accelerator increases the engine output which causes a force on the tires that results in a forward acceleration. The brake pedal causes the brakes to exert a force on the tires which results in a backwards acceleration. The steering wheel causes the tires to exert a force on the car accelerating it left or right.
TIL that deaccelerate isn’t even a word. My phone is like, wtf is that?
No, but decelerate is.
Ya but it has no meaning because everything is acceleration remember 🤣
dependencyinjection@discuss.tchncs.de 2 months ago
I am not smart but this is what I get from this meme.
It’s a play on how physics describes acceleration. In physics acceleration is just about speeding up but any change in velocity.
So:
Crikeste@lemm.ee 2 months ago
Overcook fish? Believe it or not, acceleration.
dependencyinjection@discuss.tchncs.de 2 months ago
Pray tell?
Crikeste@lemm.ee 2 months ago
Image