Sled Ride

For this assignment, I pulled my sister, on a sled, through the snow in our front yard. By calculating her acceleration, I would use that to find the force I was applying on her sled. Then by using the angle at which I held the sled, I could then find the normal force and the frictional force. I could use those two measurements to then find the force I applied on her sled.

The first step was to put a tape measure in the snow where I would pull it. I measured out 7 ft to be a scale by which I could measure her acceleration on logger pro. I put the video into logger pro, plotted the points and graphed a line of fit on her acceleration.

The video was rotated and I could not figure out how to straighten it, so her acceleration was in the negative y direction. 

I used a protractor to find that my arm was at approximately 40 degrees.  I then found online that the kinetic friction of snow and a ski, which is has the same material as my sled, is 0.05. 

I then created a free body diagram, with the equations. I solved for the Normal force in the first equation and plugged that into the second equation.

From there, I plugged the values of the mass, acceleration and gravity into the designated spots and solved for the force at which I pulled her. 

The force I applied on her sled was approximately 139.4 Newtons. 

Possible Errors

I may have made errors in my calculation of the angle of my arm. My arm looked like it stayed at the same angle the whole time, but there may have been minor tweaks in my arm. 

Also, the force I pulled her sled, was not constant throughout the ride. 

Sources

Elert, Glenn. “Coefficients of Friction for Snow.” Coefficients of Friction for Snow - The Physics Factbook, hypertextbook.com/facts/2007/TabraizRasul.shtml.