The equipment we used in this experiment were a scale, pulley, Styrofoam cup, string, track, and 4 wooden blocks.
In this experiment we had five different scenarios in which we took data for using the data collected from each we drew body diagrams to get our net force formulas and used those equations to find the coefficients for kinetic and static friction and then we used logger pro and collected data for kinetic friction and compared what we got from the computer with the kinetic friction that we solved for from our equations.
For the first scenario we are going to measure the mass of the block being pulled then we are going to add water to the cup until there is enough water in the cup to make the block move. Then we measured the mass of the cup with the amount of water that made the block move.
We continued this process always adding another block for each trial until we had four blocks total.
We gathered the data for the mass of the water that made the block move which is represented by C. and the mass of the blocks represented by B.
Using our data we made a graph of friction and time and the slope of our graph was our coefficient for static friction which turned out to be .2912.
For the second scenario we used a force sensor to examine kinetic friction. First we calibrated the force sensor, then we measure the mass of the block we were going to pull. We tied the string to the force sensor and pulled the block. logger pro recorded the force of the pull in newtons for each trial and we recorded the data on the white board.
The mean values that we got for friction came from the data collected by logger pro in the bottom photo .
We used the data for Normal Force and Friction to create a graph and the slope of our graph was the coefficient of kinetic friction.
Next placed one block on a horizontal track and then we raised the track until the block slide down the track and at that point we measured the angle that it took to move the block. Using the measured angle and the measured mass of the block we used free body diagrams to get our net force formulas to calculate the coefficient of static friction
For the fourth scenario we set up the system so that the track is at an incline steep enough so that the block will accelerate down the track. We measured the angle of the incline of the track. And we attached a motion sensor at the top of the track so that we could measure the acceleration of the block as it went down the track. Using the data for the acceleration and the angle measured we are able to calculate the coefficient of kinetic friction using the formulas derived from the free body diagrams as we did in the bottom pic.
For scenario five we had a two mass system on a track and we using the coefficient of kinetic friction we had to derive an expression to find the acceleration of the block on the track using a large enough mass to accelerate the system. The mass that we used to accelerate the system was .05 kg . Using the mass and the static friction from scenario four we were able to find the acceleration of the block.
Next, we used a motion sensor and logger pro to measure the actual acceleration of the block using the same hanging mass and compared the acceleration we got from logger pro with the acceleration that we got from the calculation. As you can see from the bottom photo the slope of the graph is the acceleration which turned out to be .4564 while our calculated acceleration turned out to be .459 m/s^2 . Our results were pretty close to each other but not perfectly the same because there many factors that could have lead to some error.
In conclusion, we learned out to calculate the static friction and kinetic friction coefficients depending on what we were given. we also saw how static friction is greater than kinetic friction. And we were to calculate acceleration of a system and compare it to the acceleration we recorded form logger pro.
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