Momentum, Impulse, and Smashing into the Boards
By: Julia Pimentel
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Momentum:
- Momentum, "p", is given by p = mv
Here, Ryan skates into the boards at a constant velocity and comes to a stop. Momentum would not be conserved in this case as the boards apply an outside force on Ryan, bringing him to a stop.
Impulse:
- Impulse, "J", can be written several different ways; J = Ft = Δp = mΔv
*** Utilizing these equations, we can find the force that is exerted on Ryan by the boards! ***
Here's How:
First, Ryan's weight is known to be 160 lbs or 72.575 kg
Using logger pro, we can find his velocity by analyzing the position vs. time graph shown below
The velocity given by the slope of the line is 2.966 m/s
Lastly, we know that he was in contact with the boards for approximately 0.30 seconds before coming to a complete stop
Now, we can solve for the applied force using mΔv = Ft
72.575 (0 - 2.966) = F (0.30)
- 215.257 = F (0.30)
F = - 717.5 N
With hockey players who are skating at much higher speeds and are more massive than Ryan, one can only imagine how much more force it would require to bring them to a stop. This is why it is more common to see them bounce back off of the boards.
If Ryan hit another member of our group (which luckily he didn't), and if the friction caused by his skates on the ice was negligible, momentum would have been conserved because while the boards are still, a person would have moved in the opposite direction and the following set of equations would have been used:
m1v1i + m2v2i = m1v1f + m2v2f
Thank You!
A special thanks to Ryan Clary, Alyssa Pappas, Eve Zeng, Mansi Patel, Nate Thimas, and Courtney Marcos for making this day happen!
Bloopers for Your Enjoyment
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Sources:
“Momentum and Impulse Connection.” The Physics Classroom, www.physicsclassroom.com/class/momentum/Lesson-1/Momentum-and-Impulse-Connection.
“What Are Momentum and Impulse?” Khan Academy, www.khanacademy.org/science/physics/linear-momentum/momentum-tutorial/a/what-are-momentum-and-impulse.
