As part of our ongoing drive to explore stupidity, we have been practising high fives while crossing each over on opposite tacks

We quickly came to the realisation that it can seriously hurt your hand and probably even more your head should anything go wrong at the last second

Now I was not surprise as I assumed that with a speed of approximately 30k in both directions, the impact would be approximately 60k which is a decent slap in anyone's book.

However, some smart friend of mine raised a very valid point on top of making me painfully aware of my own shortcomings:

If you imagine a fix wall and 2 cars coming at it from different directions at the same time, both impact would be equal to the initial speed carried by a sole vehicle, If you remove the wall, the same principal applies.

Can anyone confirm this theory???

Mythbusters looked at this....maybe google it...

It is true as the maximum deceleration force is the same in both. Ie hitting the brick wall or another car coming at 100km/h you decelerate at the same speed.

Take two cars travelling toward each other at 30km/h, replace one of the cars with a brick wall that is (magically) doing the same speed.
So you've got a car travelling towards the wall at 30km/h, you've also got the wall travelling towards the car at 30km/h; this is the same as one car travelling towards a stationary wall at 60km/h.

Hence, two cars hitting each other head on, each doing 30km/h = the force of impact being applicable to an impact at 60km/h.

Putting a wall in between the two cars makes little difference to the force of impact.

The way they cancel each other out?

Take the two cars, place them back to back and tie them together with a strong enough cable, get the driver of each to accelerate at exactly the same pace at exactly the same time; the forward force generated by each car is equal, hence the forward forces of each car are equal and cancel each other out.
Result neither car moves. Providing the cable holds.

It is a combined impact of both speeds. Newtons laws of energy

High 5s suck dude

you never heard of the Wiggles

Fun for ya kids and saves you from gay bitch slappin

Depends on the size of the wall

^what he said, there would be some energy loss in the wall but what's the point, depends on the details

while he is standing still with his back turned and a drink in hand,only if he's bigger

Why not just take up rugby instead.

Then you can cuddle in real tight to each other's hairy butt, and no-one will think it odd or unmanly.

Woo-Yeah!! High five?

Trant said...

sebol said...
Can anyone confirm this theory???

I can confirm that it's rubbish. Sounds like one of those "A fly stops a moving train at the moment of impact" type of statements.

The impact 'force' is a result of the combined speed.

Drpoob is correct, the speeds are not combined, whether you were slapping a stationary pole/ object or something moving towards you. The deceleration is the same 30km/hr down to 0.

Jeez, I guess this is one of the weird things. The initial spec "Compare a car smashing into a wall at 30km/h with two cars hitting each other at 30km/h" is pretty specific.
I can agree that the statement is probably right then, but only for this specific case. Each car absorbs a certain amount of force whereas the wall absorbs very little (so most of the force is absorbed by the sole car)

A better experiment would be:

Smash a 30km/h car into another stationary car.
Compare that to to smashing two cars at 30km/h

Think about it, would you rather crash into a parked car at 30km/h or hit another car head-on at 30km/h?

So oceanfire seems the force is still halved even if the speed is doubled. Ie; another car or a wall. Absolutely no difference.

nice to see my 1/2 carton of coopers fuelled saturday night rant turn into a healthy SB debate. also nice but somewhat suprising to see i was right

I think you should explore this a little further sebol. maybe handslap Elroy Jetson once more, then try the same with a solid object - let me know what hurts more :)

p.s. the first aid kit is well stocked, its in the rear drivers side compartment of my car, big green first aid sticker on it. help yourself if you need it. looking forward to more rants next weekend - sunday is shaping up to be pretty similar to that other day at you know where

... and what about the guys who high 5 with a swing in their arm? Now I'm just complicating things!!!!!

yeah swear i saw something like this on mythbusters. a head on crash has less force than a car just hitting a solid rigid object. in theory you would think 2 cars at 100kmh had a head on the inpact would be like 200kmh

PFFFFFT- Engineers.....biggest waste of space going around- what would they know ?

Mythbusters proved it with plasticine and swingy things, that beats the hell out of all those theoretical equations and calculations that an engineer is scribbling on a bit of paper if you ask me.