When Push Comes to Shove...

By: Shaila Murthy


For my blog post, I decided to have one of my friends (Matt) push another one of my friends (Abby) across the ice in ice skates, so I could measure the force with which he pushed her.

In order to find Abby's acceleration, I plugged this video into Logger Pro and used the graphing software to create a velocity vs. time graph. Then, I created a linear fit line and used the slope of that line as my approximate average acceleration (it is measured in inches on the graph because we did not have a meter stick or a ruler available at this location so I had to use a piece of paper as the reference...).

Once I had her acceleration, I set up my free body diagram and my skeleton force equations:

From there, I set up the equations with the values I had, with the goal of solving for the force "F" (the force with which Matt pushed Abby). I did find, however, that I was unable to calculate this without the coefficient of kinetic friction on ice, so I did look up that value in order to solve for my desired value.

By using the force equations, I calculated that the force Matt imposed on Abby has an approximate value of 12.09 N. 👍

Sources:

1.) Koning, JJ, et al. “Ice Friction During Speed Skating.” Journal of Biomechanics, 25 June 1992, 

www.ncbi.nlm.nih.gov/pubmed/1517252.