The Chad's Gap of Waterslides!

you see they have these things called computers. they make magic man i shit you not. like one time i saw all these pictures of those people from mythbusters fucking each other. BUT IT WASN'T EVEN REAL. mindblowing
 
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Well at least hes smarter than the people who believe everything they see on the internet and has enough critical thinking skills to break it down to the facts
 
At least 50% of the people who posted reactions to this thought it was real and should be euthanised.
 
aldkjfaduiofn!!! if that was in any way possible and you wouldn't have harsh whiplash and what not when you first got sent up it would be so much fun!!!
 
I am still puzzled as to how they made it look so real. If I was 10 years younger I wouldn't have even questioned its validity.
 
"Hey Creedman, if you and your homies come on up to the gulch, you are

gonna get a good old ass kickin by me and my bros. Mack Dawg is my

nigga and youll become our bitches. Dont you worry, creedman well make

the landing nice and soft for ya after we salt the shit out of it...no

one makes a kicker in my hood. Youre a big fag creedman with a mangina.

I dare ya to come on up and hit chads. your fuckn insane. me and my

home boys are gonna come out and wreck you and the jump...dont even

think about it"

ahhhhhhh.... altarider and his unchecked anger issues make me laugh again and again.
 
the extreme waterslide into the lake looked like so much fun

now i need a hill, a ramp, a lake, and a some slippery material...
 
thats what i heard?!

me and my friends were going to hit it next summer but now we cant, guess we'll just have to hit the smaller slip'n'slide up the hill a couple miles
 
Ok so i did some math and this is my conclusion

  • What is the guy’s acceleration after he leaves the ramp?
  • What was his initial velocity leaving the ramp?
  • How high above this would he have to start?

Ok. Time for Tracker Video Analysis. Here is the y-motion for the ‘flight’:

data_tool_5.jpg


Notes:

  • The unit of scale is the height of the ramp.
  • There

    is an obvious perspective problem. As the camera pans, the angle

    between the motion and the camera is not constant and not

    perpendicular. I have no simple way to correct for this (yet).
  • From this, the acceleration is about 4 ramps/s2.
  • At

    this point, I can’t really tell if it is fake or not. The motion does

    not fit a parabola very well, but that could be because of perspective

    issues.

Now, if I assume that the acceleration in real life is 9.8 m/s2, then the ramp would be 2.45 meters tall. Using this new scale, I can look at the horizontal motion:

data_tool_6.jpg


This looks linear-ish. From this, the horizontal velocity is mostly

constant at a value of around 16 m/s (which is about 36 mph for the

metric-challenged). At least I have enough info to make some

calculations. Note that 16 m/s is the guy’s horizontal velocity, not

the total initial velocity. The initial vertical speed can be

determined by looking at the time in the air. (here is a review of projectile motion) If I assume that the guy starts and lands at the same height, then I can use:

la_te_xi_t_1_58.jpg


Since y and y0 are the same, I can solve for the initial velocity:

la_te_xi_t_1_59.jpg


From the video, ?t = 2.1 seconds. This gives an initial y-velocity of 10.3 m/s. This will give a total initial speed of:

la_te_xi_t_1_60.jpg


Putting in the values for the x- and y-velocity, this gives a

magnitude of the initial velocity of 19 m/s. Why do I care about this

velocity? Two reasons. First, I can estimate how high up the hill the

guy would need to start to get this speed. Second, this is the same

speed the guy will hit the pool. So, I can estimate the acceleration

when he lands and see how deadly it would be (I already suspect he

should be ok – think about professor splash)

How high up the hill would he have to start? If I ignore friction

(always a good place to start), then I can use the work-energy

principle to calculate this. Let me make a sketch.

untitled_29.jpg


The work-energy principle is great to use here because it

essentially deals with change in position. I will start with the

Earth-guy as my system (this means that there will be a gravitational

potential energy and NOT work done by the gravitational force). When

working with the work-energy principle, you need two positions. In this

case, that will be at the top of the hill and at the top of the ramp.

During this motion, there are only two forces acting on the guy: the

normal force from the ground and the gravitational force. The normal

force does no work since it is always perpendicular to the direction

the guy is moving. Gravity doesn’t do any work because I am using the

gravitational potential energy. If the guy starts from rest at the top

of the hill, and I set the zero gravitational potential at the top of

the ramp, then:

la_te_xi_t_1_61.jpg


I didn’t want to be too confusing about the velocity in the above

expressions. That is the velocity at the top of the ramp. If I wanted

to be consistent with the stuff from before, this would be v0. Using this stuff and solving the for the height above the ramp, I get:

la_te_xi_t_1_62.jpg


Notice that this solution does not depend on the mass of the guy nor

does it depend on the angle the hill is inclined. If I plug in the

value for the speed at the top of the ramp, then the starting point

must be at least 18 meters higher than the top of the ramp. If there is

significant friction it would need to be even higher.

It is very difficult to estimate the height of the starting point

because of the angle the camera is viewing from. There is one thing

that does not change with perspective though – time. I can get the time

it takes the guy to get from the top of the hill to the bottom of the

hill and calculate how steep the hill would have to be (again assuming

no friction). From the video, this is about 3 seconds. The ramp looks

pretty big, but I am going to use the velocity at the top of the ramp

as though it were the velocity at the bottom of the ramp just to get an

estimate of the angle of the ramp. Ok, so if he goes from 0 to 19 m/s

in 3 seconds, then his acceleration (average) would be:

la_te_xi_t_1_63.jpg


So, if this were a hill at a constant slope with no friction, how

steep would it be? Here is a free body diagram of an object sliding

down a slope.

untitled_30.jpg


I want to find the acceleration down the plane as a function of the

angle of the plane. In this case, the only force acting in the

direction of acceleration would be a component of the gravitational

force. This gives:

la_te_xi_t_1_65.jpg


If I put in 6 m/s2 in for a, then I get an angle of 40

degrees. Pretty steep – but it is a mountain I guess. I guess this is

real. But there are still some things to investigate. I will leave the

following questions for homework:

  • Suppose you are planning this “stunt” and your initial velocity

    is off by dv (some small amount). What would the resulting change in

    range be? If dv = 0.5 m/s, would the guy still land in the pool?
  • Suppose

    the coefficient of kinetic friction was 0.1. What would be the new

    velocity at the top of the ramp? You can assume that the hill is

    straight.
  • Estimate the acceleration of the guy when he hits the water. Look up the NASA g-force tolerance tables and see if he is ok.
  • Where did they get all the water to fill up the pool?
  • Who inflated the pool and how long did it take if they just used their lungs?

Homework hint. If you look at that Professor Splash jumping into a foot of water,

it will really help. In that analysis, Prof Splash is going about 15

m/s before hitting the water. Yes, that is slower than this guy, but

this guy lands in much deeper water (maybe 3 feet?) and at a

non-perpendicular angle (which means he has a greater distance to slow

down).
 
i thought this was real for the longest time, I loved it. then i found out it was a fake, im dissappointed. in everything, ever
 
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