Basketball shot - real or fake?

Nice post. But I think you meant to leave off the last line, seems like a note to yourself while you were writing.

@The Virtuosi,

HA! You are right. It was a note to myself. I removed it. Thanks!

Tee hee, you don't have to fake it. Just show the 1 out of 1000 takes that made it.
Is kinda like evolution, toss out what doesn't work, keep what does.

I suspect fake. I think, although this is just guessing, that the impact on the goal would o be a lot more violent than shown from that height. If you missed and hit the ring it would almost certainly break, and considering the number of tries you'd need to get that one, perfect hit, it would be an expensive video.

thanks, I wonder what the margins of error are in the angle thrown or initial force.

question:

if the ball landed on a young squirrel would it kill it?

the ball hits the net 3 meters above the ground.

I am not sure how much difference it would make, but I have read that the drag coefficient of a basketball is actually 0.25. Like a golf ball, the dimples trip the transition to turbulence, reducing the wake effect. I have not seen experimental proof of this value of drag coefficient. It is on my list of things to test.

It really doesn't look like he threw it that hard, but athletes can put a lot on a ball with little effort. I've seen a college bench player make a turnaround jumper from the sideline at half court.

I would position the goal after throwing a few basketballs off of the tower. Then you are relying on the ability of an amateur athlete to repeat a physical action and only have to worry about windage.

The ball is traveling close to vertical, which helps with the margin of error. The jumpers LeBron can make from the baseline (about 94 feet) are tougher.

Impact of the ball on the rim is nothing compared to a dunk. These portable baskets are pretty tough.

I'd suggest some model confirmation experiments, both real (drop a ball off of a tall building or take a road trip to that tower) and video (tracker analysis of LeBron's baseline shots). You also have the apex of the ball's flight (the form line on the elevator tower above the door) and the time to that point to calibrate your initial speed/angle estimate.

@Scott,

Good point. Really, someone needs to measure the coefficient for a basketball - or maybe this has already been done? If the coefficient is much smaller, he wouldn't have the throw the ball as hard.

You mentioned your values for initial speed, but you didn't give us the throw angle. Did you just simulate a horizontally thrown ball? I'd estimate the angle at 10 degrees or more above horizontal.

Adjusting speed and angle separately could allow you to keep your fall time accurate while getting your horizontal distance closer to the theoretical value.

(I should say that other commenters have mentioned the throw angle, but I want to address that explicitly.)

Looking at the video clip, I am going to use an initial launch angle of 21 degrees.

D'oh. Of course as soon as I post my comment I find where you answered my question. Reading skills. I need them.

@9:
You can learn all you need to know by dropping it about 100 feet and analyzing the video to find the velocity dependence of the acceleration.

I know that genuinely skilled people can put a lot more into a throw than a neophyte, but 20 m/s is 45 mph. As I recall from an experience with a pitch radar at a ballpark one time, I can throw a baseball in the vicinity of that speed by putting my entire body into it. (I know that professionals can throw twice that fast, but they're one-in-a-million freaks of nature (in the good way) who still, eventually, pull their own joints apart as often as not.) I'd characterize the video dude's throw of that basketball, which is much heaver and more awkard than a baseball, as a "casual toss."

Let's try a more quantitative approach. I've seen (real) videos of people sinking full-court shots. They look like they're throwing the ball with a whole lot more effort than what video dude was putting out. A basketball court is aobut 55 m long. Assuming a player throws the ball up at a 45-degree angle (probably not optimal for making the basket, but let's try it as a first guess), and neglecting air resistance (again, might be a problem), the player would need to throw the ball with a velocity of sqrt(((9.8 m/s^2)*(55 m))/4) = 11.6 m/s. At a (more realistic?) steeper trajectory of 60 degrees above horizontal, then the required velocity is sqrt(((9.8 m/s^2)*(55 m))/(sqrt(3)/2)) = 24.9 m/s. This is within the ranges of speeds shown in the video, but again, good basketball players look like they have to work pretty hard to put the ball up with these kinds of velocities, and video dude is not working that hard.

Barring some revision to Rhett's modelling, I'm going to guess that the video is fake.

OK, for all you skeptics out there, first required viewing before you debate me here> http://www.youtube.com/watch?v=lhbISRqSXW0. I pose this. Why would these dudes go through all that, then fake the swish shot? They shot from 2 angles and you can watch the ball leave the tower and connect with the net. I'm just a layperson and simple math tells me at what speed an object falls to earth and the time it takes to get there. The seconds from when the ball leaves the tower to the net seem correct.If you still think that the dudes faked the shot, then email or call fox6 news and have them recreate the shot and let fox6 film it.

Rhett: to alleviate the non-perpendicular to motion camera angle, can't you do some co-ordinate transformation to estimate what the projection of the true trajectory would look like from the camera angle?

I think that mapping the position of the shadow of the ball in the ground may give some extra information about the trajectory to compare with the model, as a double check.

I'm the sports anchor at the Fox TV station in Birmingham. The Vulcan statue is right next door to the station. We had two news photographers video tape these kids- it took them about 200 tries but yes, they made the shot, and no,the video is not doctored.

@rob

I have tried something like this before with limited success. It is a pain.

@Esteban,

Wow - I didn't even think about the shadow. Great idea. I am not even sure how well it can be seen in the video, I will have to go back and take a look.

@Rick,

200 tries? That is a very important piece of data - it will be useful later. Thanks!

Did they get closer as the shots progressed?

The elevation from the base of the monument to the elevation of the goal was an additional 10 feet. I am the mom of the kid who is the founder of the Legendary Shots which made this Vulcan shot. Can you compare this the the Dude Perfect shot at the Texas A&M football stadium?

@Jill,

I have seen the Texas A&M shot, and I wanted to analyze it. However, I found it was easier to get specifications of the distances with the Vulcan statue than the Texas A&M stadium. If someone has a few more details about that shot, I can probably put it together.

all i have to say is that there is no way of that ball having a 20m/s - 72km/h initial speed but i think that it isnt fake.