The myth I hate the most is that bullets have the kinetic energy of a wrecking ball causing people to fly 5 feet in the air after getting hit. Only Chuck Norris' legs have that kind of power.

What a great idea! The transit fare loss is offset by the modest health benefit of participating riders!

Expanding on this, perhaps engineers could harness the kinetic energy and charge a battery that powers the ticket machine (or just feeds back into the grid.) That idea might make more sense in a stationary bike context, but I'd love to see more of this.

I remember when I was really young, I was ridding down the back yard neighbor's driveway to my grandmother's house, I hit a railroad tie and the bike flipped, and in a panic I dropped while it was upside down only to see the bike land on its wheels and continue on for a short bit... had I stuck with it and it did the same thing it would have been epic, but odds are it would have changed the kinetics and just resulted in more pain.

They need a better name. If Play-Doh was called Kinetic Dough it never would have taken off.

Just as a historical note, the World War 2 German Stuka dive-bomber used 20mm rounds to take out Soviet tanks.

That's a shitload of kinetic energy.

I also figured it would be lower because, well, physics. I think the spinning block was ever-so-slightly lower, but they were so close, practically millimeters it seems, that I am still curious about the lack of a greater difference.

The only thing I could think of that would cause this is that the initial rate of angular rotation on the spinning mass made up for the lower amount of direct kinetic energy from the bullet.
The bullet still conveyed the maximum amount of potential kinetic energy, but instead of transferring it solely to the objects linear acceleration, it transferred half to the objects linear acceleration, and the rest to the objects rotational acceleration, and by some principle of centrifugal or centripetal force that rotational energy somehow caused the block to reach the same height.

A shot in the dark, but that's my guess.

Essentially my guess is that the bullet can only transfer so much kinetic energy to accelerate the block upwards. Above that threshold it finds other ways of disposing of this energy. Why this threshold/diminishing return might exist idk.

So yeah, I think there must be some change in the efficiency of the transfer of energy in the two examples. Does smacking the bullet right in the centre create more sound? Does the bullet deform/heat up more in the first example because the block simple can't get out of the way fast enough? You'd think that spinning a block would take comparitively little energy compared to all those other inefficiencies. Perhaps if you were to increase the velocity of the bullet you might not see that large of a difference in the height it rises - rather the block would sustain more damage, the slug would pancake more etc etc.

It does seem raher counter-intuitive though. I'd like to know the explanation.

I thought you might be overestimating the force of a thrown baseball as compared to the steel ball bearing, so I tried to do some research and run numbers to compare.

Some googling says a baseball should weigh 5-5.25 ounces (about 1/3 of a pound).

Another page and some quick calculations that I might have screwed up[ (4*pi*.5*.5*.5)/3*.283 ] say that the ball bearing might weigh about .15 pounds -- a bit under half of the baseball.

On the other hand, the fastest pitch ever recorded in MLB (by Nolan Ryan) was 108.1 MPH or 158.5 feet per second. Harder to find data on "muzzle" velocity of a slingshot, but this page suggests that some people claim some slingshot projectiles can travel at 300 feet per second, but he argues that 180 to 200 fps is probably a more realistic high end for a .50 caliber lead ball (which would probably/possibly? be heavier than the 1" steel ball since lead is more dense). Anyway, there is at the very least a slight advantage to the slingshot here as compared to the fastest pitch ever recorded in MLB. Considering the draw length and pull strength of the slingshot in the video, I'd say it is probably actually much faster than the conservative 180-200 fps number from that page.

So then you've got @cosmovitelli 's formula (mass times velocity squared). The mass of the baseball is probably double that of the steel ball, but the velocity is probably 25-90% faster (or even more) and then squared. That probably overcomes the disadvantage in mass and then some.

Then again, this is all fairly academic as you suggested because the lethality of the bullets/projectiles is dependent on them being small enough to puncture, tear flesh, break/shatter bones, etc. Apply that kinetic energy to a very small impact site. However, in spite of its large size, I bet that steel ball could do a lot of damage given its kinetic energy -- which is what I would take away from their claims of it "hitting harder". I wouldn't want to stand in front of a Nolan Ryan fastball either, but given the choice between that and the slung steel ball... I'd take the plunk and have somebody take my base for me.

kinetic energy = mass x velocity squared

Bullets kill by punching holes in vital organs, fracturing bones into the blood and slicing veins and arteries - not by impact shock.
More like poking a thin metal rod into someones body than hitting them with a heavy object.

Only in hollywood do they throw people off their feet.

Sometimes they get it right:

http://youtu.be/f8j4GIRYbZw

Kinetic sculpture by Anthony Howe - In Cloud Light has been added as a related post - related requested by oritteropo on that post.

What people with a jones for physics, kinetic energy, and the wonder of a child do with a decommissioned crane bucket....for the fucking win!

Upvote for a recent personal respect for Mr. Trampoline.....I only wish my own epic trampoline fail was captured on tape, it would have surely garnered over 100 votes for anyone who uploaded it....the physics involved alone would have been enough fodder for a paper on the wonders of kinetic energy vs. threshold displacement energy

My understanding is that a correct autorotation is NOT accompanied by a hard landing. However, it IS very difficult to pull off (hard---what a pun!), the closest personally analogy I can think of, being docking a boat by chopping the throttle while still tens of yards away from the dock, casting it up alongside just So---with all the kinetic energy elegantly spent before kissing the dock side.

The helicopter analogy, again, to my knowledge, is that once engine failure is clearly happening, you flatten the pitch, give up the lift the blades were generating, start falling and preserve main rotor RPM as much as possible---and you get exactly one chance and one chance only to pull pitch (make the rotor blades bite the air) at just the right distance above the ground to decelerate the helicopter just as all the rotational energy of the blades finishes spending itself in generating that last, final iota of lift--and then you kiss the ground.
Or not.

Dear SciFi,
Fuck Lasers. Do not Laser. Do Kinetic. DId nobody think to weaponise this technology that allows you to accelerate mass to relatavistic speeds?

Wouldn't mind one of your lightsabers though.

I don't get it. This "kinetic typography" is a thing? I feel dumber for having watched it.