How Do You Calculate the Coefficient of Friction in a Ramp Experiment?

[Unidh4x0r]

1. Homework Statement
given: a large block ramp, a smaller block (one side wood, other side felt), and a stopwatch
refer to this picture:
http://01.edu-cdn.com/files/static/w...SLIDING_01.GIF

you don't know weight, or θ but I do have the measurements for the x and y axis

2. Homework Equations



3. The Attempt at a Solution
I did five trials each for the wood on wood side and the felt on wood side. I measured the x and the y-axis along with the time it took for the object to slide all the way across the large ramp.

1. Homework Statement

find coefficient of friction, static and kinetic

2. Homework Equations
Fnet=ma
vf=vi+at



3. The Attempt at a Solution

What I have so far:
Procedure:
1. Measure the large block ramp
2. Increase theta until the block starts moving and stop. During this process, use a stop watch to measure how long the small block takes to travel the ramp.
3. Repeat this process for both the wooden on wood and felt on wood.
Explanation and justification:
By measuring the large block, you get the distance the smaller block will travel, whether it’s wood on wood or felt on wood. The stop watch measures how long it takes. With this information, we can get acceleration, which would then lead us to calculate the coefficient of friction.

For kinetic friction, I think it's something like this:
Fnet=ma
-k=ma
u_kF_f=ma

Not sure on rest...

 

[Delphi51]

This gets quite complex when you have a ramp at an angle. The angle effects how the force of gravity is resolved into a normal force causing friction and a force along the ramp causing acceleration. You might start by studying the explanation in your textbook or something like this: http://library.thinkquest.org/16600/intermediate/force.shtml

 

[Unidh4x0r]

What would be the proper steps to solve for both the static and kinetic friction though? I took measurements of the x and y lengths of every trial.

 

[Delphi51]

I have no way of knowing what x and y are. Your diagram does not display; perhaps it is only accessible to students enrolled. Perhaps you could copy it and put it up on photobucket for us.

 

[asteriatic]

Your procedure is a good start in determining the coefficient of friction. However, there are a few things that can be improved upon. First, it is important to note that the coefficient of friction depends on the normal force, which is the force perpendicular to the surface that the object is sliding on. In this case, it would be the weight of the smaller block. Therefore, it would be helpful to know the weight of the block in order to accurately calculate the coefficient of friction.

Secondly, it is important to take multiple measurements for each trial and calculate an average in order to reduce errors and increase the accuracy of your results. This can also help in identifying any outliers or inconsistencies in your data.

For the equations, you are correct in using Fnet=ma and vf=vi+at. However, for the calculation of the coefficient of friction, you would use the equation Ff=μN, where Ff is the force of friction, μ is the coefficient of friction, and N is the normal force. You can use the measured time and distance to calculate the acceleration of the block, and then use that in the equation Fnet=ma to solve for the force of friction. From there, you can calculate the coefficient of friction for each trial and take an average.

For the kinetic friction, you are on the right track. The only thing I would mention is that the negative sign is not necessary, as it will cancel out when solving for the coefficient of friction. Also, make sure to label your units and show your work clearly to make it easier to follow your calculations.

Overall, it seems like you have a good understanding of the concept and the necessary equations. Just remember to take multiple measurements and include the weight of the block in your calculations to improve the accuracy of your results. Good luck with your lab!