Naked Science Forum

Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: Petrochemicals on 25/03/2018 17:21:16

Title: Is kinetic energy absolute ?
Post by: Petrochemicals on 25/03/2018 17:21:16: As in this you tube video

https://www.google.co.uk/url?sa=t&source=web&rct=j&url=https://www.youtube.com/watch%3Fv%3DqV4xVAYCK8Q&ved=0ahUKEwim0JDy7ofaAhWGblAKHSW7DLQQo7QBCB4wAQ&usg=AOvVaw2XOw1TrjMQ_8qb3RS68JfP

The ball destroys the bat. If it where the other way around would the bat destroy the ball or is the ball just harder ? Is it pressure causing this as the bat is supported by air at the same static relative position as it ? Why does the static air pressure not destroy the ball ? Or does the ball actually have a greater kinetic energy and therefor an absolute content of higher energy staus that is contrary to the concepts of relative force and equal and opposite force ? They are meeting head on ie 180 ?
Title: Re: Is kinetic energy absolute ?
Post by: Colin2B on 25/03/2018 18:38:19: Looking at the video, the ball appears to disintegrate. I’ve done same with candle fired out of a musket at a board, it punches a hole, but then it is mush.
If you could move the bat at the same speed the ball was moving and hit a stationary ball, then the same would happen. Trick is to get them moving fast enough so the ball doesn’t collapse before it gets through.
Title: Re: Is kinetic energy absolute ?
Post by: wolfekeeper on 26/03/2018 01:46:02: FWIW kinetic energy is not absolute. Kinetic energy is relative to the frame of reference. If the bat is moving then you get completely different kinetic energy than if the ball is moving. But for any reference frame energy is conserved within that frame.
Title: Re: Is kinetic energy absolute ?
Post by: Petrochemicals on 27/03/2018 22:39:06: Thank youcolin. You know i put that video on there without watching 5he slow mo. Some of the do not bother. Watching a few more videos there is an element of thermal heating explained in it alot like shaped metallic charges. The ping pong ball heats to desrtructive temeratures. I know its not got the rodelement, but the bat is too thin for that.

Do you think the other way a bat would efen survive 1000mph, or disintegrate before it hit ? Still amazes me though.
Title: Re: Is kinetic energy absolute ?
Post by: Petrochemicals on 27/03/2018 22:58:52: Yup, at 1.44 in in this video of a rail gun you can see how thenprojectile dimishes itself over inpacts, fire and shrinkage said the vicar.