Complicating the World Lines of Spheres

[Shapedoctor]

Do not attempt!

 

 

It's been quite a few years since I took physics and my math is rusty. I was kind of curious about how fast that van is traveling and if it's even possible to figure out.

 

Also, I wanted to test my ability to post images here.

 

Have whatever kind of day you want to have.:rolleyes:

[ronthepon]

A cool excersise to have some math fun on, I'd say!

 

Well, first you need to get an idea on how fast the frames are going on in the pic. That can be done by mesuring the amount of time the balls take to go up and down. For that, you'll have to guess how high he chucks them.

(Can make use of newton's simple laws for the answer)

 

Then, we can take two landmarks in the image (eg: two of those... blackish lines on the 'wall' thing nearby.) After guessing the disance between two of those lines (seems like two-three meters to me), we can gauge the amount of time the car takes to pass by them.

 

That should be easy enough. A rough figure, but an intellegent guess.

[ronthepon]

or were you talking about the van that travels by? We will have to use the concept of relative motion then. How about mesuring the amount of time that van takes to pass the whole frame? using the perspective angles the van makes with the camera at various times should tell a good deal about how far it is from the camera. That should help us in finding out.

[Shapedoctor]

Thanks ronthepon. I think I'm most curious about the van in the background. The juggler's vehicle speed should be ~96kph. The cement barricades are probably somewhat standardized and I might be able to measure one when I have some time for an adventure. I have access to the spheres, the juggler's vehicle, and the larger original video of this.

 

For the time being I'm just going to leave this gif up to see what can be deduced from it alone.

[Boerseun]

Being a juggler myself, that .gif is definitely not running real time. And if we don't know how far it was slowed down, there's no real way to deduce the speed of the vehicle. Judging by the motion of the balls, it seems the clip is running about 50% real speed, which means he must have been going at one helluva speed when the movieclip was made.

 

Or maybe I've just got a crappy browser.

 

You never know.