With this being the first day for students in many schools in North Carolina and the upcoming Michigan game I think it might time to post this again.

I made this for my Physics class after the game and I was able to get my hands on a video of the game. Since I examined the video and made this question I have watched a better side-line camera angle and there have been some advances in video analysis. Both of which could make my measurements more accurate. I literally made a digital file/DVD of the file I had and counted frames as I hit frame advance with a remote. Some of the measurements are a bit of guess work based on Corey's height.

The extra credit is hard as heck and I had to make a huge spreadsheet to iterate through a bunch of variables. I'll try and post the spreadsheet on Friday if anyone really wants to look at that. Lots and lots of numbers.

Game Winning Blocked Projectile

Corey Lynch, a senior Physics major at Appalachian State University and 4-year starter as Safety on the ASU football team, successfully blocked a field goal attempt by the University of Michigan football team. Corey was 4-yards (3.66-meters) in front of the place kicker when the football hit him in the chest. At this point the football was 4 feet 9 inches (1.45-meters) above the ground. Based on an analysis of the game video, 5 video frames passed between the kicking of the ball and the field goal attempt being blocked. At 30 frames a second for video signals in the United States, this is equivalent to 0.17 seconds.

a) With what velocity did the football leave the kicker’s foot? (Magnitude and direction.)

b) What was the velocity of the football at the moment of impact with Corey Lynch?

Assuming constant velocity, Corey ran the ball back from ASU’s 33-yard line to the 10-yard line of Michigan as time ran out. This run of 55.7-meters took 7.2 seconds.

c) How fast was Corey Lynch running at this time? Answer in m/s.

Does this answer sound reasonable? Explain.

Extra Credit: Assuming the same speed off the kicker’s foot, at what range of angles would the ball need to be kicked to clear Corey Lynch’s upper reach (8-feet) and still have the range and height to clear the goalpost. The ball was kicked from the 27-yard line. You will need to convert to metric units and investigate the height and distance the football would need to travel to be a good field goal.

I promise rep points for the correct answers, which I will post on Friday.

I got a headache from just reading this. No wonder I did not do well in Physics.

The correct answer is 34 over 32.

AppSt94 wrote:The correct answer is 34 over 32.

RP

Mt nose is bleeding..................

AppSt94 wrote:The correct answer is 34 over 32.

I have nothing to say about this but -

Come on Man!!! - Are you kidding??? - I barely (and I mean barely) got through Freshman algebra my Senior year in college --- Happiest "D" I ever made --- Physics - yeah

Physics!! Yeah, b!+ch!!!

The whole Corey Lynch discussion playing out in another thread is taking the wind of the the sails of this problem a bit. The other thing taking the wind out of the sales is the fact that I posted the version that had a wrong video frame count. Instead of 8 frames it should have been 5 frames. That shortens the time the ball is in the air, which basically means the football was moving faster. I thought I had the correct version based on the time-stamp of the file but after I did some calculations I was coming up with speeds that would not get the football to the goal line and that did not seem correct.

The assumption is no air resistance, which is a big factor, but without bringing in differential equations (fourth semester of Calculus essentially) and have some numbers to deal with the size, shape and texture of a football I could not deal with air resistance. The only force acting on the football is gravity once it leaves contact with the kicker's foot.

If anyone is really interested I can show my work, but at present it is a bit of a mess on a piece of paper that may include either a splatter of blood or a melted piece of Fudgesicle (R)

Wrong Frame Count:
Off the kicker's foot:
a) Horizontal component of velocity 13.6 m/s
Vertical component of velocity 6.7 m/s
The net velocity, which is what I was asking for is 15.1 m/s at 26.3 deg above the horizontal.

Impact with Lynch's chest:
b) Horizontal component of velocity 13.6 m/s (that is constant for this problem
Vertical component of velocity 4.0 m/s
The net velocity, which is what I was asking for is 14.2 m/s at 16.6 deg above the horizontal.

Running down field:
c) 7.74 m/s. Reasonable? Yes, A 40 yard split time of 4.5 s is equal to 8.1 m/s

EC) Using the 5 fps count the ball was going to slow and would not have made it to the goal line based on my spreadsheet work I did. There were some complicated math with the unkown angle that took a spreadsheet running through angles from 0 to 90 degrees in 0.1 degree increments to get some numbers for an answer.

At 8 frames a second the EC does produce some angles that would have cleared Lynch and had the range to make it to the goal line and still be 10 feet above the ground. Of course this does not count being wide one side or the other.

c) Same answer

a) Horizontal component of velocity is now 22.0 m/s. 27.7 m/s is 62 mph for reference.
Vertical component of velocity is now 9.5 m/s
The net velocity, which is what I was asking for is 24.0 m/s at 23.3 deg above the horizontal.

b) Horizontal component of velocity is now 22.0 m/s.
Vertical component of velocity is now 7.9 m/s
The net velocity, which is what I was asking for is 23.4 m/s at 18.1 deg above the horizontal.