The physical act of walking requires the presence of friction. You need the force of friction between your shoes and the ground to point in the opposite direction of your motion in order to push off of your toes and move forwards.
At Colgate, no matter where you are going, you are almost always walking up a hill or down a hill. In both scenarios, friction is paramount in getting you where you need to go without sliding. Almost every day, I make the long, arduous trek down to Case Library. I usually walk from my dorm, so most of the walk is downhill. Due to the indirect set up of the path that leads to the library, many people decide to cut through the grass to go down the hill, ignoring the paved walkway. While it is faster to walk through the grass, it is more dangerous due to the risk of falling and then sliding or rolling down the hill. As seen in Engineering Analysis of Vehicular Accidents, written by Randall K. Noon, the coefficient of friction for wet grass, 0.20, is much smaller than the coefficient of friction for wet concrete, 0.60. On an angle, the force of friction is equal to μmgsinθ where θ is the angle of the incline or decline. When μ is a small value, as is seen in the case of wet grass, the magnitude of the force of friction is smaller, increasing the likelihood of slipping and falling forwards down the hill.
At Colgate, no matter where you are going, you are almost always walking up a hill or down a hill. In both scenarios, friction is paramount in getting you where you need to go without sliding. Almost every day, I make the long, arduous trek down to Case Library. I usually walk from my dorm, so most of the walk is downhill. Due to the indirect set up of the path that leads to the library, many people decide to cut through the grass to go down the hill, ignoring the paved walkway. While it is faster to walk through the grass, it is more dangerous due to the risk of falling and then sliding or rolling down the hill. As seen in Engineering Analysis of Vehicular Accidents, written by Randall K. Noon, the coefficient of friction for wet grass, 0.20, is much smaller than the coefficient of friction for wet concrete, 0.60. On an angle, the force of friction is equal to μmgsinθ where θ is the angle of the incline or decline. When μ is a small value, as is seen in the case of wet grass, the magnitude of the force of friction is smaller, increasing the likelihood of slipping and falling forwards down the hill.
A smaller μ is not the only threat posed when descending the grassy hill to get to the library. It is also important to be cautious about the route you take down the grassy hill. You should not take a very steep route because it will also increase your chances of slipping. The x-componenet of the force of gravity is equal to mgsinθ. As θ increases, there is an increase in both the component of the force of gravity that is parallel to the incline and your chances of slipping.
While it may appear faster and easier to cut through the grass to get to the library, this route should only be taken with great caution and on a day when the grass is not wet.
Sources: https://saferroadsconference.com/wp-content/uploads/2016/05/Peter-Cenek-Frictional-Characteristics-Roadside-Grass-Types.pdf
http://thecraftycanvas.com/library/finding-forces-acting-upon-objects-on-an-inclined-plane-or-ramp-with-free-body-diagrams/
No comments:
Post a Comment
Note: Only a member of this blog may post a comment.