Group1_4_ch6

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 * Lab Group 12**
 * Period 4**

**Lab: The Law of __Conservation of Energy__ ** Part A - Stephanie Wang Part B - Hella Talas Part C - Jonathan Itskovitch Part D - Stephanie Wang

**Objective:**

1) What is the relationship between changes in kinetic energy and changes in gravitational potential energy?

**Hypothesis:**

1) The total energy initially is going to equal the total final energy**.**


 * Station 1:** Find the __speed__ of the cart at the bottom of the incline. Initial velocity is 0. The heights of the top and bottom of the incline were measured with a meterstick. A CMV was sent down a metal track, attached to a ringstand. Mass the cart. The length of the cart is the distance. It went through the picket fence, where time was recorded, and this helps find the velocity.




 * Station 2:** Find the __speed__ of the ball as it leaves the launcher, and when it is 9.6 cm from the floor. Measure the height from the floor to the projectile, and from the floor to the other picket fence. Mass the ball. The ball is launched from a projectile, and goes through two picket fences, one just where the launcher is, and one that is 9.6 cm from the floor. Two measures will be recorded on Data Studio for each of the times in the picket fences. First measure the vertical height from the floor to the launcher. Then set the time in data studio to time in gate for time for the initial velocity and final velocity. Measure the ball with a meterstick, as that is the distance it goes.



Find the speed of the cork at the bottom of the pendulum. The cork is released from a height of 20cm above the picket fence, located at the bottom of the pendulum. The height is the initial height, and the cork will pass through the picker fence like a swing, and the time is recorded in it. This helps find the speed. The diameter of the cork is the distance.
 * Station 3:**




 * Station 4:** Find the max height of a ball on the top of the incline. Measure the height of the ball as it first leaves the incline and goes down. Then, measure the height of the highest point the ball reaches on the other side (the first time), with a meterstick. Mass the ball with a __balance__.




 * Station 5:** Find the speed of the ball as it leaves the launcher. A projectile launches a ball vertically, into the air, with an initial speed. A picket fence is placed at the tip of the projectile, __measuring__ the time in the fence. The diameter of the ball is the distance, measured with a meterstick. Measure the max height of the ball (if the tip of the projectile is 0) with a meterstick as well. When the ball goes back down, it goes through the picket fence __again__, and measures the final time. This helps finding the final velocity. Also mass the ball.




 * Station 6:** Find the speed of the __roller__ coaster at the top of the loop. A ball is released from the top of the track, and goes through this __roller__ coaster. A picket fence is placed at the top of the loop, which measures the time it takes for the ball to pass. The diameter of the ball is the distance. This helps us calculate velocity. Initial velocity is 0. Mass the ball. Measure the heights of the top of the track, as well as the top of the loop.



Data Table: Stations, Heights, and Speeds

Analysis: Data Table: Percent Difference and Percent Energy Loss

Our hypothesis says that the total initial and total final energy will be equal. This is because of the Law of Conservation of Energy, which states that energy cannot be created or destroyed. This means that the initial and final energy must be equal to each other. This hypothesis proved to be mostly true. In some of the experiments, friction (workout) was present, so the initial energy and final energy were a little bit different. Since we took the class average of all the data from all 3 class periods, we got 16 trials of each station. This means that our results should be pretty accurate. This is because the results that were too high balanced the ones that were too low. For station one, we got a 1.19% percent difference, and a 1.20% energy loss. This means that our results were excellent for this station, and the total initial energy almost exactly matched up with the total final energy. For station 2, our percent difference was 32.33%, and our percent energy loss was 38.57%. This can be attributed to a source of error. We got good results for stations three and four, which both yielded percent differences and percent energy losses that were around 10% to 15%. For stations five, our percent difference was 24.43% while our energy loss was 27.835. The same error that occurred for station two could have happened in this station. We also did not get excellent results for station six, as our percent difference was 36.62% and our percent energy loss was 30.96%. There was probably a lot of energy loss because of the presence of friction. For this lab, there were multiple sources of error. We assumed that no work was being done. However, friction (workout) played a role in stations 1,4, and 6 and altered our results. To fix this, we could have coated the tracks in ice, which would create a frictionless surface. Another source of error is the measurements taken. For example, the ramp should be the same height for all the trials. However, some groups got different heights for the ramp. The problem might be that the ramp was not tightly clamped to the stand. To fix this problem, the ramp should have been more tightly clamped to the stand so it couldn't slip down or move up. In the second station, we assumed that the diameter of the ball passes through the photogate. However, the launcher is inconsistent, so the photogate could have measured the time for a chord of the ball, not the diameter. If this happened, then the measured velocity would have been lower than the actual velocity of the ball. This lab can also be applied to real life. Station six featured a track that is in the shape of a roller coaster. Engineers who design roller coasters for theme parks must make sure that they are safe and work properly. They need to find the minimum speed for a cart to not fall off the tracks at the top of an upside down loop.
 * Conclusion:**

Lab: The Law of Conservation of Energy for a Mass on the Spring
Part A - Hella Talas Part B - Hella Talas Part C - Jonathan Itskovitch Part D - Stephanie Wang


 * Objective:**


 * To directly determine the spring constant k of several springs by measuring the elongation of the spring for specific applied forces.
 * To measure the elastic potential energy of the spring.
 * To use a graph to find the work done in stretching the spring.
 * To measure the gravitational potential and kinetic energy at 3 positions during the spring oscillation.


 * Hypothesis:**
 * The spring constant for each spring will be the slope on a graph of their position vs. time. We know this because of Hooke's Law.
 * Softer springs will have a smaller k constant than harder springs because they will elongate more.
 * The total amount of energy will be the same at the min. height, the max. height, and at the equilibrium. We know this because of the Law of Conservation of Energy.

For part A, the purpose was to find the spring constant coefficient in newton meters of several springs. To find this, we used different colored springs, red, yellow, and green. We began by measuring the distance of the spring to the tabletop with a meter stick. Then we began to add masses to the springs and found its displacement. Since weight is force and the displacement is displacement, the points go n the graph, and the slope is the spring constant. For part B, the purpose was to find velocities at different points on a period (the spring went up and down) and figure out whether energy has been conserved. A motion detector is at th tabletop, and a spring bounces up and down wih a mass attached to it. Displacement is recorded in data studio, and a periodic graph is formed. We find certain values, and conclude whether energy has been conserved.
 * Procedure:**

Trial run for part B


 * Measuring displacement for part A**


 * PART A:**


 * Data Table: K Constants of Different Springs**


 * Graph: K Constant of Different Springs**


 * Data Table: Class Values of K**




 * PART B:**


 * Data Studio Graphs**


 * Data Table: Energy Conservation**

Analysis: Calculations:



Discussion Questions:**
 * 1) Do the data for the displacement of the spring versus the applied force indicate that the data for the spring constant is indeed constant for this range of forces?

Yes, the data does in fact indicates that the spring constant remains constant for the range of applied forces. Each of the three lines in the first part of the lab represent the three springs, and each of the Force versus displacement graphs are linear. Since the spring force constant is in Newton-meters, we know that the spring constant remains constant. It is just the slope of the graph.


 * 1) How can you tell which spring is softer by merely looking at the graph?

The spring that is softest is the one that has the lowest spring force constant, or slope on the graph. This shows that there is an increased displacement for a given force. It resists less.


 * 1) Describe the changes in energy of the hanging mass, beginning with it starting at rest, you pulling the mass down and then releasing it, and then the mass cycling through one complete period.

Technically speaking, there shouldn’t be a change in energy, due to our prior knowledge of the Law of Conservation of Energy. Whatever changes that may have occurred is simply because of experimental error. When at rest, the hanging mass does not have kinetic energy; it only has potential. When it is released, the mass goes straight down, going until a low point, and builds elastic potential energy as the spring stretches. Gravitational energy goes down because it is going closer to the tabletop, and kinetic energy increases because of vertical acceleration downwards. After it reaches this low point, the hanging mass goes straight up, through the equilibrium point, and up to a max point on top (where the spring does not stretch). Elastic potential energy decreases, GPE increases, and KE increases. It goes through many periods of this.

Our hypothesis that the softer springs would have a smaller k value was proven to be correct. The softest spring, the red one, had the smallest spring constant k. Our hypothesis that the spring constant of a spring is equal to the slope of its position time graph was also proven to be correct, as you can see from our graph. Also, our hypothesis that the total amount of energy would be the same at the min. height, the max. height, and at the equilibrium was correct. This is why we set the total energy for the different heights equal to each other for the analysis.
 * Conclusion:**

Our results were pretty okay, but not spectacular for part A. Our percent errors ranged from 19.15% (yellow) to 30.32% (green). This is not very good, as percent error should always be below 10%. However, the box with the spring constant said that there could be a difference of 105, so this needs to be taken into account. Our results can probably be attributed to the various sources of error we encountered. When compared to the class data, our percent differences ranged from pretty good (13.14% for yellow) to poor (24.66% for yellow). For part B, we wanted the total energy to be the same at the min. height, max. height, and equilibrium. Our results were close, but not equal to each other. The percent difference was very low for equilibrium, only .29%, but higher for min. height and max height, which both had percent differences around 14%. These results can be explained by the numerous sources of error present.

There were a few sources of error for this experiment. If the spring with the masses added was measured while the spring was still moving, we could have gotten an erroneous result. To fix this, we should wait until the spring stopped moving to measure it. Also, we could have measured the spring a few different times, and taken the average. For the second part of the lab, a source of error would be the motion detector. If the motion detector was not directly under the cardboard, then the graph it produced would not have been accurate. To fix this problem, make sure the motion detector is set directly underneath the cardboard. Also, the motion sensor measures position in increments, and might not have actually recorded the actual min. height or max. height.

This lab also applies to real life. Bungee jumping is when someone jumps over a cliff or off a bridge, connected to a bungee cord. The bungee cord must be able to hold the person’s weight, and can’t be so stretchy that the person will hit the ground.

Rollercoaster Project Written Report - The Amusement Park of Dreams

 * We proudly present America's next favorite roller coaster, the Amusement Park of Dreams....**

Drawings: Pictures


 * As you can see, the Amusement Park of Dreams is not only designed for thrills, it is a treat for the eyes! Just as many people will be lining up to take pictures of this engineering marvel as to ride the roller coaster.**

Trials:

media type="file" key="Movie on 2012-02-17 at 10.52.mov" width="300" height="300"

Circular motion in our roller coaster:

Circular motion is when an object uniformly rotates along a circular path. At the top of our roller coaster, all the kinetic energy is accelerating to the height of the vertical loop. That energy is then conserved as potential energy "mgh" which allows the ball to complete the loop. One can see there is circular motion because normal force and weight are downward and at the horizontal loop, normal force is a centripetal force. The roller coaster is moving in circular motion, therefore, there is a centripetal acceleration at the vertical and horizontal loops.

Discussion of Concepts:

Energy conservation states that, in theory, the amount of energy should be the same at the beginning and end of an event, in this case a rollercoaster. The coaster is dropped from an initial high point with no speed, and ends with no height and some speed. The equation makes it so that the initial energy and work is equal to the final energy. The key thing to mention is this work. During the entire ride, work is being done because of the friction force opposing motion. Therefore, because of this work out, the final energy will technically be smaller than the initial energy. For conservation to truly work, there needs to be a frictionless surface. So why is there friction in the first place? It is due to Newton’s laws, particularly the second law. If a free body diagram were to be drawn of the marble at any given point of the coaster, here is how it would be drawn. Weight would be going down, Normal fore would be going perpendicular to the surface of the coaster, and the friction force would be going in the opposite direction of the coaster. Yes, even though the surface is paper, and the coefficient of friction may be low, there still is friction! So then we look at the equation F=ma. Because the only axis where acceleration occurs is on the x, I can say the following: All of these derived equations come to show that, because there is a friction force present in the rollercoaster, the marble is decelerating throughout the entire course. And because of this friction force opposing motion, work out is being done. Work is done when a force causes displacement, and work is measured by Force*displacement. Since the force is friction, and displacement can be measured by the length of track, work out can be calculated. Power is simply the rate of work. It is how much the force displaces something in a second, minute, etc. Also on these equations is the Normal force, being equal to weight times cosine of the angle. The normal force is the apparent weight; it is what one feels like they weigh on the rollercoaster; the actual weight does not change. That is why, on the top of the hill, when the angle is at 90 degrees, the apparent weight is zero. At the top of the hill, people feel like they don’t weight anything while they actually do. The assignment later asks the groups to come up with a theoretical spring that will stop the coaster in case the brakes fail (because the cart can fly off)! Coming up with the correct spring system can be easily found using Hooke’s Law, whereby the force the spring exerts is equal to the opposite of the spring constant times x, or the distance that the spring compresses. The equation looks like F=-kx. Using F=ma would be useful in We could also use LCE, because all of the initial energy would equal the elastic potential energy in the end.

Citations: http://www.4physics.com/phy_demo/HookesLaw/HookesLawLab.html

Presentation: Our rollercoaster is a wonderful design, but it is a work in progress. We have fun loops, curves, and hills all over the place. The coaster is also mostly safe. The acceleration in the coaster is all good except for the top of the loop, but that can definitely be fixed with time. There is also a lot of safety precautions, such as going up the initial hill in slower time to make sure initial velocity is zero at the top. There is also a lot of friction generated in the coaster to make sure it doesn't go too fast. So while it is fun, the kids can feel safe as well.

Data Table: RollerCoaster

Calculations:

GPE

The EPE, 0.0514 J, is equal to the Total Energy!

Proposed Hill: Discussion:


 * As you can see, our roller coaster will be a wonderful addition to your theme park!**

Lab: Elastic and Inelastic Collisions Part A: Stephanie Wang Part B: Hella Talas Part C: Jonathan Itskovitch Part D: Stephanie Wang

**Objective: What is the relationship between the initial momentum and final momentum of a system? Which collisions are elastic collisions and which ones are inelastic collisions?**

<span style="font-family: Arial,Helvetica,sans-serif;">**Hypothesis:** <span style="font-family: Arial,Helvetica,sans-serif;">The initial and final momentum should be equal because of the Law of Conservation of Momentum, which states that the total initial momentum will be equal to the total final momentum. Since elastic collisions are collisions in which kinetic energy is conserved, we predict that the motion/motion (sticking together) will be an elastic collision. Since inelastic collisions are collisions in which kinetic energy is not conserved, we predict that rest/rest (explosion), rest/motion (sticking together), rest/motion (bouncing apart), and motion/motion (bouncing apart) will be inelastic collisions.

<span style="font-family: Arial,Helvetica,sans-serif;">**Pictures of set-up/ methods and materials:**

<span style="font-family: Arial,Helvetica,sans-serif;">This lab is done with a series of collisions, which are later determined to be either inelastic or elastic. There are carts that are first massed with an electronic scale. They are then pushed along an aluminum rail and are somehow collided with another cart. It can be an explosion, crashed into a car at rest, crashed into a car in motion. It doesn't matter; but each scenario is tested. The purpose of the lab is to test the conservation of momentum, so to test that, in each case, a mass bar is added to the cart in each scenario. This can test if the velocity can make up for the difference in mass, thereby conserving momentum. The initial and final velocities of the carts are found in data Studio in v-t graphs. We have to make sure the signs are right because there can only be one positive-x axis, so the graphs are not 100% accurate. Low percent differences show the momentum has been conserved throughout the collision.



<span style="font-family: Arial,Helvetica,sans-serif;">**Video of Procedure:**

<span style="font-family: Arial,Helvetica,sans-serif;">media type="file" key="Movie on 2012-03-09 at 12.18.mov" width="300" height="300"

<span style="font-family: Arial,Helvetica,sans-serif;">**Data Studio Graphs:** <span style="font-family: Arial,Helvetica,sans-serif;">

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<span style="font-family: Arial,Helvetica,sans-serif;">

<span style="font-family: Arial,Helvetica,sans-serif;">**Data Table: (In)elastic Collisions** <span style="font-family: Arial,Helvetica,sans-serif;">

<span style="font-family: Arial,Helvetica,sans-serif;"> **Sample Calculations:**

<span style="font-family: Arial,Helvetica,sans-serif;">**Analysis Questions**

Momentum is not conserved in this experiment because most of the collisions were inelastic. The initial kinetic energy and the final kinetic energy were not equal. For example, in the rest/motion (sticking together) type of collision, the initial KE ranged from .098 to .092 and the final from .051 to .049. The percent differences were from 8% - 38%, which shows how much the KE was not conserved.
 * 1. Is momentum conserved in this experiment? Explain, using actual data from the lab. **

<span style="font-family: Arial,Helvetica,sans-serif;">The cart with less mass has the higher velocity because the mass and velocity have an indirect relationship meaning, if the mass is large, the velocity will be smaller. This is because of the equation p=mv, and we assume that p is constant.
 * 2. When carts of unequal masses push away from each other, which cart has a higher velocity? Explain why this is. **


 * 3. When carts of unequal masses push away from each other, which cart has more momentum? **

<span style="font-family: Arial,Helvetica,sans-serif;">It does not matter what the masses of the carts are, the momentum MUST remain equal always. Since p=mv, momentum is the same, the masses are unequal, the smaller-massed cart must make up the deficit with a higher velocity.


 * 4. Is the momentum dependent on which cart has its plunger cocked? Explain why or why not. **

<span style="font-family: Arial,Helvetica,sans-serif;">No, it is not dependent on this at all. The only two factors involving momentum are mass and velocity. Moreover, since the plunger should technically have equal effects on both carts during the collisions, there is no concern about which cart has the plunger.

<span style="font-family: Arial,Helvetica,sans-serif;">**Conclusion:** <span style="font-family: Arial,Helvetica,sans-serif;">We found that our hypothesis was correct. The total initial and total final momentum were equal to each other, so momentum was conserved. The elastic collisions had a small difference between the initial and final kinetic energy since kinetic energy was conserved. The inelastic collisions had large differences between the initial and final kinetic energy since kinetic energy was not conserved. Our hypothesis that the motion/motion (sticking together) collision would be elastic, and rest/rest (explosion), rest/motion (sticking together), rest/motion (bouncing apart), and motion/motion (bouncing apart) would be inelastic collisions was proven to be correct. <span style="font-family: Arial,Helvetica,sans-serif;">We got low percent differences for the most part for momentum, which is very good. Most of our percent differences between the initial and final momentum was below 5%. The reason the percent difference was so high for the rest/rest (explosion) is because of the way the experiment was conducted. Since the carts started at rest, the momentum for both carts was 0 (using the equation p = m*v). Therefore, there will be a large percent difference since the carts are both moving (and therefore have momentum) at the end. One source of error is the mass of the carts. We did not mass any of the carts. We just used the mass that was written on them. For example, if a cart had "499 g" written on it, we assumed this was the mass of the cart. However, pieces like the plunger could have broken off the cart from the time the mass was written to the time that we used it, so the mass could have been erroneous. This would lead us to get inaccurate results. To fix this, we should simply mass the carts before we use them. Another source of error was the track. Even though we tested the level-ness of the track by placing a cart on it and seeing if it rolled towards one end, it was impossible to get the track completely level. Even though we propped up the lower end by placing a notebook under the track, the carts still sometimes rolled towards it without being pushed. To fix this, we should use a level to make sure the track is lying completely flat on the table. Then, we should have made sure the track was level after each collision, as the movement of the carts could have caused the track to become unbalanced. Also, in the future, we could have been more careful with the motion sensor since sometimes, it picked up the motion of our hand instead of the carts. This lab can be related to many real life situations. For example, the collisions can all be viewed as small scale car crashes. Car companies need to make sure their cars are safe and protect passengers in case of accidents. They need to see if bump off bumpers are safer (in this lab, the bouncing apart collisions) or if the crush bumpers are safer (in this lab, those would be the sticking together collisions). The explosions can be seen in firecrackers or fireworks.

= Lab: Ballistic Pendulum = A: Jonathan Itskovitch B: Hella Talas C: Jonathan Itskovitch D: Stephanie Wang Objective: What is the initial speed of a ball fired into a ballistic pendulum?

Hypothesis: We hypothesize that the three difference measurement techniques will produce similar initial velocities. The photogate will probably produce the most accurate results, and the LCE technique will probably be a little less accurate since there is a little energy lost.

Methods and Materials: We tested for the original velocity in three different ways. First, with a photogate timer. We connected the photogate to a computer and calculated how much time it took for the ball to go through it. Of course, it was put just outside the launcher, which is clamped to the table with a clamp. We measure the diameter of the ball with a meterstick, and simply did v=d/t. For kinematics, we used a meterstick to find the height to the ground and the horizontal distance to the ground. the exact points were recorded by carbon paper taped to the floor. Doing projectile kinematics gave us the initial velocity. Finally, we did conservation of energy and momentum, launching the ball into a pendulum that swung up to a certain angle theta, which we measured. We also found the center of mass of the pendulum and calculated the length to the end of it. We then massed the ball and pendulum in order to solve the work-energy and momentum equations. These three methods should give us a relatively similar initial velocity, which it did.

Video: media type="file" key="Movie on 2012-03-16 at 14.54.mov" width="300" height="300"

Data Table: Ballistic Pendulum

Calculations: Discussion Questions:
 * 1) In general, what kind of collision conserves kinetic energy? What kind doesn’t? What kind results in maximum loss of kinetic energy?
 * An elastic collision would conserve energy, while an inelastic collision would not conserve energy. An inelastic collision, such as a car crashing into a tree, would cause maximum loss of kinetic energy, as all velocity is lost.
 * 1) Consider the collision between the ball and pendulum.
 * Is it elastic or inelastic?
 * The collision is inelastic
 * Is energy conserved?
 * Due to the inelasticity of the collision, energy is not conserved.
 * Is momentum conserved?
 * Even if energy is not conserved, momentum is concerned because of the consideration of mass. Velocity lost in one cart is gained by the other. This is stated by the LCM.
 * 1) Consider the swing and rise of the pendulum and embedded ball.
 * Is energy conserved from the moment just before the ball strikes the pendulum to the moment the pendulum rises to its maximum height?
 * Energy is not conserved, again, because it is inelastic. The ball sticks to the catcher so velocity is lost and therefore energy is lost.
 * How about momentum?
 * Momentum is conserved, as it would be in all scenarios, since LCM applies to all collisions.
 * 1) It would greatly simplify the calculations if kinetic energy were conserved in the collision between ball and pendulum.
 * Calculate the loss in kinetic energy as the difference between the kinetic energy before and immediately after the collision between ball and pendulum.
 * What is the Percent Loss?
 * 1) According to your calculations, would it be valid to assume that energy was conserved in that collision?
 * No, we cannot assume energy is conserved as there is nearly a 30% energy loss.
 * Calculate the ratio M/(m+M). Compare this ratio with the ratio calculated in part (b). Theoretically, these two ratios should be the same. State the level of agreement for these two quantities for your data.
 * 1) Go to [] Select “Ballistic Pendulum” from the column on the left. What is the effect of increasing the mass of the ball? What is the effect of increasing the pendulum mass? Try it. (NOTE: You have to read “Student Notes” first before you can run the simulation.)
 * Mass increase would increase the final height and theta of the pendulum. However, increasing the pendulum mass would do quite the opposite. That is because momentum must remain constant, and a higher mass is compensated by lower velocity. Therefore, the height is reduced.
 * 1) Is there a significant difference between the three calculated values of velocity? What factors would increase the difference between these results? How would you build a ballistic pendulum so that momentum method gave better results?
 * 2) There is not a significant difference between the calculated values of velocity. Each time, with careful procedures, we were able to get small percent differences. No matter what the case is, the velocity is consistent from the launcher. Factors such as inconsistency of the launcher, poor measurements, and a bad photo-gate would contribute to a bigger difference. To improve the pendulum, I would have a digital reader of the measurement theta so it is more accurate. I noticed that even a degree difference means a lot! I would also try to reduce the stickiness of the ball to the catcher.

Conclusion Our hypothesis was partially accurate. The three different techniques we used yielded similar results. When we used kinematics, we simply launched the ball with the launcher and treated the situation like a projectile. We measured the height of the table and launcher, and the distance the ball traveled. Using this information, we found the time the ball was in the air, and from this, the initial velocity. The average initial velocity for the ball using kinematics was 2.365 m/s. We also used a photogate to determine the initial velocity. We set the photogate to "time in gate" and put it in front of the launcher. We found the diameter of the ball and used the equation v=d/t to find the initial velocity. The average initial velocity using the photo gate technique is 2.458 m/s. The third technique we used was using the Laws of Conservation of Matter. We used the ballistic pendulum model and got an average initial velocity of 2.506 m/s. We hypothsized that the photo gate would have the most accurate results and the LCE technique would yield the least accurate results. During our lab however, we found that the highest percent different, 5.719%, comes from the photo gate and the lowest percent difference, 0%, comes from using LCE. However, since our highest percent difference is only 5.719%, we got excellent results. Obviously, since the percent error is not 0% for all the trials, there were a few experimental errors. First off, the launchers were not consistent. Even though we set them to the lowest setting each time, they launched the balls at different distances. To fix this, we could put in new springs in the launchers and warm them up before using them. Another error is that could have occurred is that the photo gate could have been set on an angle, capturing the ball for more or less of the time it was actually supposed to. To fix this, we should make the sure photo gate is completely straight by using a level. We also could have measured poorly for the kinematics portion of the lab. To fix this, each group member should have made measurements, and we should have taken the average. Another way to get more accurate results is to perform more trials for each technique. This lab was an example of an inelastic collision. These are pretty common in real life, and examples include glancing car crashes. Projectiles are also pretty common, and examples include cannons and throwing a ball. The experiment we conducted is comparable to a person throwing a ball off a cliff or building. It is important to study inelastic collisions like ballistic pendulums because they help us design better cars and vehicles. Projectiles are also important as most sports involve some form of a projectile.