Why can you not jump off a falling object to break your momentum?
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I assume you mean like the old question about a falling elevator, and if you jump up at the end you can save yourself. The problem is that you do indeed slow your falling speed slightly, and you transfer some momentum to the object you jump off of, but it’s not nearly enough to make a difference.
You can, but your jump might accelerate you by 1 m/s or so upward. If you’re in a freefall with another object and falling 20 m/s, a jump up at the last moment means you hit the ground at 19 m/s instead, and still suffer grievous injuries or die.
I’m not a specialist but i believe it has to do with innertia, basically your body is falling at the same speed as the object, even with different masses, it’s like when you’re in a vehicle and it stops suddenly, your body will keep moving forward.
Well, if your legs were strong enough, then you could. Although if that were true, you wouldn’t need to break your fall.
It can be explained through classical physics! (Simplified in the context of this subreddit)
Let’s say you’re standing on the ground. Gravity of Earth is pulling you down, but why don’t you fall through the floor? You remain still because the floor is pushing *upwards* with the same force that you are pushing down with. If you apply enough force to, let’s say, a pencil – it will resist until the wood is no longer strong enough to push back with equal force, and it will snap. But before then, it will push back with the same force that is applied to it.
This is because, according to classical physics, every reaction has an equal and opposite reaction. Rockets fly upward because they shoot exhaust downward.
Now, back to free falling.
When you stand on the ground, or fall on it, it will push back at you with equal force. Your bones and internal organs, like the pencil, may not be able to apply such a force without breaking. If you were falling down at 50 MPH (American here) you would need to jump with enough force to send you upward at 50 MPH to cancel it out and nullify your fall. Your legs are not strong enough to withstand such a force, and if they were, you wouldn’t need to break your fall since they would exert the same exact force by simply absorbing the force of impact.
You could. If only you could jump hard enough. Problem is, you can’t really jump hard enough. To fully arrest your momentum, even from a small height (say 2 meters) would require more leg muscle energy than (almost) anyone has ever been able to produce in a single movement at a rapid enough speed. You have to fully overcome the ~20m/s of acceleration that you’ve already experienced just to maintain your current height, let alone come back up slightly.
As long as the object is only falling at the speed of a person jumping you can.
One data source puts a human jump at around 2.4 meters per second.
The landing speed, is also about 2.4 meters per second.
Human terminal velocity is 66 meters per second, a volkswagen beetle’s terminal velocity is about 160m/s.
A human cannot generate enough downward force to counteract falling velocity. So unless you’re falling at about the same speed someone lands from a jump, not really worth it unless you’re going to convert some vertical energy into lateral energy by rolling.
[Let’s start with this video](https://youtu.be/BLuI118nhzc?t=23)
The ball, while resting in the cannon, is still moving because it is on the moving truck. The cannon is fired so that the forward velocity coming from the truck and the backward velocity from the cannon balance out, and the ball just falls straight down. If the cannon were less powerful, the ball would move to the left, despite the cannon pointing right, because the speed from the truck would overpower the speed from the canon, so the net velocity ti to the left.
If you are in a falling elevator, you are falling at the same speed as the elevator. If you jump, you are adding upward momentum but it still nets out that you are falling very quickly.
The thing that confuses people is that because we can only detect movement relatively (as in compared to something), we see that we would move “upwards” compared to the elevator around us, but it and whoever is in it is still falling.
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