Question

Why Perpetual Motion Is Not Possible?

Answer 1

The projectile will most likely be slowed down by air resistance or friction.

Answer 2

@kittiwitti1 Agreed.. Can u get some example for that...just to understand how that works..

Answer 3

I alaud u for sharing thank you...

Answer 4

*aplaud

Answer 5

It's "applaud" and in case you didn't know, you can click the blue button for the best response from user :]

Example of slowing down is like rolling a ball on the ground, friction (even smooth surfaces have some jagged parts) will slow it down; If you throw the ball up it will come down because of gravity AND air resistance.

Answer 6

@kittiwiti1 The ball doesn't fall down because of air resistance. It's called resistance because it's stopping the ball from falling. It's fairly unnoticeable for larger objects, but if you drop a leaf, feather, or piece of paper, you can see that air resistance is much greater.

On the moon there is almost no air, so there is not really any noticeable resistance to objects falling. So if you drop a feather and hammer at the same time while on the moon, they will hit the ground at the same time. And if you don't believe me, watch this: http://www.youtube.com/watch?v=5C5_dOEyAfk

Answer 7

You spelled my name wrong -_-

Answer 8

It didn't come up when I typed in the first few letters anyways.

Answer 9

What's important isn't your name, it's how air resistance works. See, we both got something wrong.

Answer 10

I'm sorry if this offends you, or anyone else who reads this, but I really don't care right now.
It's 8 am in the morning and I was working through the night without sleep, so I must go to bed asap/immediately.
Have a good day.

Answer 11

Haha alright.

Answer 12

Since some idiot (not you, you're fine) made me stay on here for a few more minutes I just want to address the concern you brought up.

A ball falls from midair because of gravity, but because of AIR RESISTANCE, it falls more slowly than it would in a vacuum. Similarly, if you throw a ball horizontally, air resistance will push back on the ball moving forward, therefore slowing it down considerably more than it would move in a vacuum.
Does that solve the problem?

Answer 13

Seems about right. There's something incredibly addicting about physics isn't there? =D

Answer 14

It must be the difficulty level, and the fact that certain people like to poke and dig at difficult ideas and topics till they get the right answer.