if terminal velocity is the fastest an item can free fall, then if you were to shoot an item downwards, faster then it’s terminal velocity, would it slow down, or maintain that same speed? If it does slow down, what force is slowing it? Would it work the same way in a vacuum?
In: Physics
Friction with the air would slow it down, same way comets burn up because without air in space they reach the atmosphere going faster than terminal velocity.
It slows down, as terminal velocity is the speed where drag from air being in the way is equal to gravity. If it moves faster then drag is stronger and the object slows down because it’s fighting against air.
For the 2nd question, no, it would not work the same because there is no terminal velocity in a vacuum. Terminal velocity only makes sense when there’s an atmosphere to provide a counteracting drag force.
What about shooting downward in that huge vacuum where they did the blowing ball feather test?
Think about the trajectory of a golf ball off the tee. The initial horizontal velocity is much faster than it’s terminal velocity so it does not make a parabola. It shoots out then sort of drops in at a much steeper angle than it was launched.
It might help to think of “terminal velocity” as “the point where an object is going fast enough through air that the air pushing back stops its acceleration”.
In other words, the force of air on an object is a function of how fast the air is moving past it. So as the difference in speeds increase (either through faster air or faster object), that force increases. If the speed is increasing because of gravity (a relatively constant force), eventually the force of the air caused by that speed will match the force of gravity.
So if you start with a higher speed? Then the force of the air will be greater, which will slow the object down until gravity catches up to keep the object falling.
And while all of that assumes air is relatively constant, if you change the air’s density it will also decrease how much force it can cause. This decreases all the way down until it reaches 0 in a vacuum. So in a vacuum, that force of air acting against gravity won’t be doing anything, translating into an infinite terminal velocity.
Terminal velocity is the fastest an object can travel while falling outside of a vacuum. Inside of a vacuum, the sky’s the limit, so long as you have the energy to propell yourself at an ever increasing speed in an infinite direction.
Latest Answers