Transcript Presentation7 - Titan Physics 2009

Physics and Football
BY: Ian Ramdeen, Chris, David, Evan Harrison, and Brent Richardson
S
Football
S American football is obviously popular in the U.S.,
especially in the South.
S Did you know that physics can also be found in football
such as a football being a projectile, momentum of a player,
force applied in a tackle, and forces used in a kick?
Projectile in football
•
A projectile is any object that can
be thrown.
•
In football quarterbacks throw
the football for several miles at
quick speeds. If a quarterback
wants to throw a long pass, then
he is going to have to throw at
the right angle and right velocity.
Practice Problem
S If a quarterback throws a football at 20m/s and at an angle of 60
degrees, how far did he throw the ball?
S Formula: R=Vo^2 sin (2 theta)/g
S Theta=60 degrees V=20m/s G=9.8m/s^2
S Solve for R
S Solution: R=20^2 sin (2*60)/9.8
S 400sin(120)/(9.8)=35.348 meters
Physics Problem
S If the same qb throws a football at 25m/s and at an angle of
50 degrees, how far did he throw the ball?
S Solution: R=25^2sin2(50)/9.8
S 63 yards. Wow! What an impressive throw! He gets my
MVP vote.
Momentum
S
Everyone knows that momentum
is a measure that is equal to mass
times velocity.
S
This applies to football in this
manner because football players
of different sizes are running at
fast velocities.
Physics Problem
S If a 125 kg (275 lb) lineman is running down the field at 9.8 m/s,
what is his momentum.
S Formula: p=mv
S M=125 kg v=9.8 m/s
S Find p (momentum)
S Solution: p=125 (9.8 m/s)
S
=1225 kg-m/s
New Problem
S If this same lineman runs at 7.5 m/s, what is his
momentum?
S Solution: 125(7.5)=937.5 kg-m/s
Tacking and Impact
•
One of the biggest concepts of
physics applied to football is force.
A force of a tackle can have huge
impacts. If the impact of the tackle
is huge, that can lead to a serious
injury. If a running back is running
with a huge momentum, a sudden
tackle can come as a huge shock.
•
(Rolando McClain gave this player
a huge shock with this strong
tackle).
Physics Problem
•
If a running back has a momentum of 950 kg-m/s, and the tackle
occurs in .6 seconds, what would the force of the tackle be?
•
Formula: F=impulse/t
•
Impulse (Momentum but written as impulse in this case): 950 kg-m/s
•
t=.6 seconds
•
Find the Force
•
Solution: F=(950 kg-m/s)/ (.6seconds)=1583 N
New Problem
S If McClain tackles former Auburn running back Ben Tate in
.4 seconds, and his momentum is 1000 kg-m/s, what is the
force?
S Solution: F=1000/.4=2500N
Physics and kicking
•
Physics especially applies to the
instance when a placekicker is
trying to make a field goal. He has
to make adjustments in order to
make the attempt. He has to kick
the ball at the right angle and has
to kick the ball with a good force.
He also needs to kick the ball well,
so a good acceleration will enable
the ball to go through the goal
post. A good time while the ball is
in the air enables the ball to go
through the goal post.
Physics Problem
•
A place kicker must kick a football from a point 40 m from the goal and clear the
crossbar 3.05 m high, and the ball leaves the ground with a speed of 25 m/s at an angle
of 50 degrees to the horizontal at an acceleration of 9.8 m/s. How long does the ball
stay in the air?
•
Formula: D=ViT+(1/2)A(T^2)
•
Given Vi=25m/s A=9.8 m/s D=40m T=?
•
40=25(T)+1/2(9.8)(T^2)
•
4.9(T^2)+25T-40=0 (multiply each side by 10)
•
40=25(T)+4.9(T^2) =-250 +/- the square root of 140900 divided by 98 seconds.
References
S http://www.lcse.umn.edu/speces/labs/catapult/index.html
S http://entertainment.howstuffworks.com/physics-of-
football3.htm
S http://answers.yahoo.com/question/index?qid=200809300
92439AA1Sgc8