ElI5 – Can someone explain terminal velocity to me?
In: Physics
Suppose that you jump off a building. Initially your velocity is zero. After you jump, your velocity will increase by 9.8 m/s for every second i.e acceleration due to gravity is 9.8 m/s^2. So with this acceleration you will also experience force opposing your movement which here is meant as drag force which usually is because of air resistance. More the acceleration with time more you will experience drag force. There will be a point where your gravity force will be equal to drag force and buoyant force(not significant).The velocity at that point is called Terminal velocity. It is the point where you will no more experience any acceleration.
Air can push on things with a lot of force – anybody who has stood in a strong wind knows this. However it doesn’t have to be the air moving – if you move through the air then it will push back on you in a similar way. If you’ve stuck your hand out the window of a moving car you also know this.
Well, falling from very high places (eg: jumping out of an airplane) will involve moving through air very fast. That’s a strong wind and will push against you. The important part is that the faster you move the stronger the air pushes back against you.
Well gravity’s strength is nearly constantly no matter how fast you are falling or how high you jump from. (This isn’t technically true, but within the atmosphere it’s close enough). As you fall wind resistance gets stronger and stronger while gravity is at a fixed strength. Eventually wind resistance matches gravity and you stop picking up more speed, falling at a constant speed. This speed is terminal velocity.
How you fall matters though. With your arms and legs spread out there’s more air resistance and terminal velocity will be slower. Assume the “Superman flying” pose and point straight down and there’s less air resistance and terminal velocity will be way faster.
It’s a result of our atmosphere. When you first fall, the force of gravity speeds you up, but the air is making a drag force in the opposite direction. The faster you go, the stronger the drag. Terminal velocity is the speed when drag force perfectly cancels out the gravity force, so you don’t speed up any further.
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