A very nice and inspiring commercial from Nike. However, a flag went off when I saw this. What about that kid jumping off the 10 meter platform at the end? Was that real? Did they really let that kid jump? I am sure the insurance company had a fit over this.
Well, is it even real? Let's check.
Video Analysis
Really, it is a nice video for analysis. The camera is stationary and only seems to pan without any zooming. The camera view is also fairly far away so perspective shouldn't be a problem. Really, the only difficulty is in guessing the scale. I assume a 10 meter platform means that it is 10 meters from the platform to the water. You have to guess where the point on the water is that is right below the platform.
With that, it is just a matter of loading the video into a video analysis program like Tracker Video. Here is the plot of the vertical motion of the boy.
The quadratic fit to this data gives the following function for the vertical position (as a function of time):
What does this all mean? Well, let me start with the last part. The 8.276 meters at the end is the vertical position of the boy at time t = 0 seconds. This is not 10 meters. Why? Well, I started the video analysis before he actually jumped off the platform. This is the position he would have at the start if he was accelerating the whole time - so he would be lower than 10 meters and moving up.
The stuff in front of the t term is the vertical velocity of the boy at time t = 0 seconds. Again, this assumes he was moving up before he started going down. Remember, the fit is dumb. It just fits an equation to the existing data. It doesn't know the boy is jumping off a platform.
For the last term, consider the famous kinematic equation for an object with constant acceleration:
Here you see the term in front of the t2 is 1/2 times the vertical acceleration. That means that the -5.29 value is just 1/2 the vertical acceleration. This would put the vertical acceleration at -10.58 m/s2. Yes, this is not the expected value of 9.8 m/s2, but it is close.
So is it fake? Well, this doesn't show anything that says it has to be fake. It is either real or a clever fake. If I had to pick, I would say real.
Bonus Speed
How fast was the kid going when he hit the water? Here is a plot of speed vs. time from Tracker Video.
From this, you can see he would have a vertical speed of about 14.5 m/s (about 32 mph) when he hits. Yes, the scale is off a little bit so he would perhaps be moving slower. It's still going to hurt.
