Sep 17 2014 - Modeling friction forces

Purpose: Utilize wooden blocks to find the friction forces acting on the blocks in various situations, and also calculate the acceleration of the system.

This is a motion sensor, which is the apparatus that we used in order to get our data into our computer, such as position, time, velocity, etc.

This is a force sensor, which is the apparatus that we used to calculate the kinetic friction acting on the wooden blocks as we dragged them.

Explanation: First we are going to find the static friction force acting on the wooden blocks by attaching a string and a pulley connecting the blocks and a cup filled with water. After that, we are going to connect a force sensor to the wooden blocks to calculate the kinetic friction that acts on the blocks. Then we are going to build a ramp and find at which angle the blocks start to slide so that we can calculate the static friction of that system. After finding the static friction, we are going to increase the angle of the ramp so that the block slide with constant speed so that we calculate its kinetic friction. The finalize, we are going to create a system using weights, and a pulley that will pull the wooden block from the bottom of the ramp to the top of it, and by doing this we are going to calculate the acceleration of the system.

This is the system that we created using the wooden block and the cup of water to find the static friction.

 This data table shows the friction force obtained from, 1,2,3,4 wooden blocks respectively. We used those numbers to create a graph where we would find the coefficient of the static friction.

This is the graph from the data table above, as we can see, points 2 and 3 are a little off, probably due to uncertainties and irregular surface.

This is a graph obtained from using the force sensor to calculate the kinetic friction of the wooden blocks, we did the same calculations for all 4 blocks.

This is the ramp that we created to find the angle which the block starts to move and find the static friction. We also used this ramp to calculate the kinetic friction by increasing the angle of the ramp.

This is the graph that we used in calculating the kinetic friction for the angled ramp.

 This is how we calculated the acceleration of the system, as possible to see, the weight on the right will pull the wooden block if I stop holding it.

 This is the data table from the system that we run to calculate the acceleration.

This is the graph of the system used to find the acceleration obtained by the wooden block being dragged.

 These calculations were used in the first part of the lab, where we utilized the cup of water to find the static friction of the system. Notice that part two did not require calculations, because all we did was use a force sensor to find the kinetic friction.

 These calculations were used in the third part, where we found the the static friction of the system by creating a ramp inclined with certain angle.

 These calculations were used in the fourth part, where the increased the angle of the ramp in order to find the kinetic friction of the system.

The handwritten part of top of this picture are the calculations used for us to find the acceleration in the last part of the lab, where weights pulled to wooden block from an inclined ramp.

Summary: We started this lab by using a cup of water attached to 1,2,3,4 wooden blocks to find the static friction of them. By using those numbers in a data table, we could find the coefficient of static friction in the system. We then, attached the wooden blocks to a force sensor and by using those numbers in the computer, just like the first part, we were able to find the coefficient of kinetic friction. After this, we created a ramp with certain angle, where the block would start to move, and that would give us the maximum static friction in the ramp system. When the angle and friction were found, we increased the angle significantly, such that the wooden block would slide with certain speed, and from that we were able to calculate the kinetic friction in the ramp system. To finish the lab, we attached a string connecting some weights and the wooden block in order for us to find the acceleration in which the block was pulled by the weights.