Pulley Lab
Kristen Sierman
Lab Report: Experiment #7
Group #4
October 16th, 2012
Forces on a Pulley System A. Statement of the Problem
The purpose of this lab was to address the following questions: how does the acceleration of a pulley system depend on the mass of the driving objects? And how does the acceleration of a pulley system depend on the mass of the driven object? To achieve this, a dynamic track was set up with a string attached to a cart. The string was part of a pulley system (the pulley was at the end of the track) and connected to a mass hanger, which was vertically suspended. First, the mass of the cart was kept constant (500g) while the weight of the hanger varied (25g, 45g, 65g, 85g, and 100g). In the second part of the experiment, …show more content…
Graph (1)
In part one of the experiment, the mass of the cart was constant throughout the five trials while the mass of the hanger varied between 25g-100g. Graph 1 shows that as the mass of the hanger increased, the acceleration increased as well. This can also be shown by using the equation [1/(mc/mH)+1]g = a.
Table (2) Mass of hanger = 25g Mass of Cart (mc) | Acceleration | 500g | 0.475 m/s2 | 750g | 0.298 m/s2 | 1000g | 0.225 m/s2 | 1250g | 0.145 m/s2 | 1500g | 0.130 m/s2 | | |
Graph …show more content…
The mass of the cart ranged from 500g-1500g. As the mass of the cart increased, the acceleration of the system decreased. This is consistent with the formula [1/(mc/mH)+1]g = a. Table (3) Mass of cart stays the same and mass of hanger changes Mass of Hanger (mH) | Theoretical Acceleration | Observed Acceleration | Percent Error | 25g | 0.467 m/s2 | 0.450 m/s2 | 0.036% | 45g | 0.809 m/s2 | 0.840 m/s2 | 0.038% | 65g | 1.127 m/s2 | 1.240 m/s2 | 0.100% | 85g | 1.312 m/s2 | 1.730 m/s2 | 0.319% | 100g | 1.633 m/s2 | 2.000 m/s2 | 0.225% | The fourth run (85g) was the trial with the highest error. This could possibly be due to friction, which was assumed to be zero in the formula although there was still a small amount of friction between the track and the cart.
Table (4) Mass of hangers remains the same and the mass of the cart increases Mass of Cart (mc) | Theoretical Acceleration | Observed Acceleration | Percent Error | 500g | 0.467 m/s2 | 0.475 m/s2 | 0.017%
Lab Report: Experiment #7
Group #4
October 16th, 2012
Forces on a Pulley System A. Statement of the Problem
The purpose of this lab was to address the following questions: how does the acceleration of a pulley system depend on the mass of the driving objects? And how does the acceleration of a pulley system depend on the mass of the driven object? To achieve this, a dynamic track was set up with a string attached to a cart. The string was part of a pulley system (the pulley was at the end of the track) and connected to a mass hanger, which was vertically suspended. First, the mass of the cart was kept constant (500g) while the weight of the hanger varied (25g, 45g, 65g, 85g, and 100g). In the second part of the experiment, …show more content…
Graph (1)
In part one of the experiment, the mass of the cart was constant throughout the five trials while the mass of the hanger varied between 25g-100g. Graph 1 shows that as the mass of the hanger increased, the acceleration increased as well. This can also be shown by using the equation [1/(mc/mH)+1]g = a.
Table (2) Mass of hanger = 25g Mass of Cart (mc) | Acceleration | 500g | 0.475 m/s2 | 750g | 0.298 m/s2 | 1000g | 0.225 m/s2 | 1250g | 0.145 m/s2 | 1500g | 0.130 m/s2 | | |
Graph …show more content…
The mass of the cart ranged from 500g-1500g. As the mass of the cart increased, the acceleration of the system decreased. This is consistent with the formula [1/(mc/mH)+1]g = a. Table (3) Mass of cart stays the same and mass of hanger changes Mass of Hanger (mH) | Theoretical Acceleration | Observed Acceleration | Percent Error | 25g | 0.467 m/s2 | 0.450 m/s2 | 0.036% | 45g | 0.809 m/s2 | 0.840 m/s2 | 0.038% | 65g | 1.127 m/s2 | 1.240 m/s2 | 0.100% | 85g | 1.312 m/s2 | 1.730 m/s2 | 0.319% | 100g | 1.633 m/s2 | 2.000 m/s2 | 0.225% | The fourth run (85g) was the trial with the highest error. This could possibly be due to friction, which was assumed to be zero in the formula although there was still a small amount of friction between the track and the cart.
Table (4) Mass of hangers remains the same and the mass of the cart increases Mass of Cart (mc) | Theoretical Acceleration | Observed Acceleration | Percent Error | 500g | 0.467 m/s2 | 0.475 m/s2 | 0.017%