moving help: Jumping up on a train moving forwards.. - Help.com

anythingwhatever
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Edinburgh, U8, GB

Jumping up on a train moving forwards..

If I’m on a train traveling forwards at say 90mph and I jump vertically into the air, why do I land where I took off from and don’t end up slamming into the end of the train car?

I asked my dad and he though I was crazy. But now I have a theory.

Both the train and I are traveling forwards at 90mph. When I up into the air I don’t suddenly stop moving forwards, I continue to move forward at 90mph (0mph relative to the train) and would continue doing so if i could remain in the air without falling due to gravity until such times as air resistance and friction would slow me to a speed slower than the train and then I’d move backwards in the car. Does that make sense?

Can someone provide a nicely worded explanation of what is happening when I jump up in a train car and land (as far as I can tell) in the same place?

This open post was written 1 year, 4 months ago | V/U/S: 505, 4, 4 | Edit Post | Leave a reply | Report Post


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Since writing this post anythingwhatever may have helped people, but has not within the last 4 days. anythingwhatever is a verified member, has been around for 3 years, 1 month and has 116 posts and 918 replies to their name.

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potatobreadrules offline Verified User (2 years, 1 month) Long Term User Shouts: 1 #
An Undisclosed Location | 1 year, 4 months ago (1 hour, 7 minutes after post)

your theory’s right, both you and the train are moving at 90 mph so you’re at 0 relative to train.
BUT jumping around a train at 90 mph is silly. sit down quietly before you hurt yourself or someone else.

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Rocco. offline Verified User (1 year, 5 months) Long Term User Shouts: 19 #
An Unknown Location | 1 year, 4 months ago (1 hour, 7 minutes after post)

Well, you answered it yourself.

Because you are jumping relative to the train, the train will still carry you unless ground that is not moving with the train interferes. The air friction is stopped because the train is enclosed. If, for example you were to jump vertically in a non-enclosed area, you would be swept away.
In a convertible, with the lid open, throw a tennis ball up. The tennis ball will rise, stay for a moment as it loses it’s momentum, but because the air is now pushing against it, it will be thrown behind you. Now, close the hatch and repeat. This time, when the tennis ball loses it’s momentum and there is no air pushing it, it will simply fall back into your lap.

Hope this helps, and I hope I made even a little bit of sense…

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~LazyDaze~ offline Verified User (2 years, 6 months) Long Term User Shouts: 239 #
An Undisclosed Location | 1 year, 4 months ago (9 hours, 57 minutes after post)

yeah I agree, your moveing at the same speed as the train, which is a good job really if you want to see if you can smash into the back of it at 90mph :O

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ejohnso offline Unverified User #
An Unknown Location | 1 year ago (4 months after post)

In a word: inertia. That which is in motion, tends to stay in motion. Gravity acts to pull you towards then center of the earth, but has no effect on your lateral movement. Try this: stand on your tippy-toes just as the train is starting from a stop? Why do you fall? Again, inertia - there has to be a force acting upon you to change your velocity. Once your moving at 90 mph, you will stay moving at 90 mph until some force acts upon you to slow you down. Jumping up in the air doesn’t change the fact that you were moving laterally at 90mph before, during, and after your jump. A “normal” force pushes up from the ground to keep you from falling down, and when the train stops, you will again feel that force.

When you stand perfectly still on flat ground, how fast are you moving? “You’re not moving.” you say? The diameter of the earth is roughly 7925 mi. The circumference of the earth is then pi times that, or about 24,897 mi. A point on the equator covers this distance in 24 hours, so:

(pi * 7925) / 24.0 = 1037.3800741541297

But you don’t live on the equator, so how fast does the average person in Scotland move when they are standing perfectly still?

But the earth doesn’t just hang there in space. It’s moving around the sun. You’re moving a lot faster at night relative to the sun than you are during the day, and at the same speed as the earth at dawn or dusk. But what are those numbers.

On response to a different post, you are cute. Don’t try to cure that. Cute beats out hot hands down. “Cute” has to do with a package deal and compliments the whole package, not just how you look. Plenty of people are “hot”, yet ugly.

Hope you’ll see this new reply to your old post and think a bit.

An admirer from America

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