1 How does the height of a ball in freefall affect the coefficient of restitution on a hard surface? Please provide a description of the investigation. Your description should be one to two paragraphs and should outline what you would like to investigate and how you plan on investigating it. I want to investigate how the height a rubber ball is dropped at affects the change in its initial and first rebound height. I will have a meter stick in place beside a tile/surface, and I will set my phone or the Loggerpro camera analysis device to record the height I drop the ball at, and the ball’s rebound height. I will then drop the ball at various heights and record this data. To have a measure of elasticity, I decided to calculate the coefficient of restitution, which measures the elasticity of the collision through the ratio of the final and initial velocity of the ball. I will use the measured heights to calculate the initial and final potential energy of the ball, and use those values to find the ball’s velocities right before and after the collision. If possible, I will also try to factor in air resistance in the calculations. I will then be able to determine the coefficient of restitution for each height and draw conclusions. Why is it interesting to you? In your response you should discuss a broader context than just "because I like it". The response should be more than one sentence/word. I used to play tennis, and liked throwing and playing with the tennis balls because of how bouncy they were rather than actually playing the game. I wanted to understand the elastic properties of tennis balls and how much energy they can retain after impact from different heights. I could also use a rubber ball in this experiment, as tennis balls have a pressurized rubber core, or just use a tennis ball itself. State your independent variable. Height the ball is dropped at (m) Explain how you will measure and change your independent variable. I will measure the heights through a fixed vertical meter stick State your dependent variable. Coefficient of restitution Explain how you will measure your dependent variable. If it will be processed (calculated), you should include a brief description of the process I will calculate the initial and final heights of the ball, then use those values to calculate the respective values of potential energy. I will then set this equal to the ball’s kinetic energy, find the initial/final velocities, and determine the coefficient of restitution for each height. List any control variables AND FOR EACH ONE briefly explain HOW you will control it. (please format each one on it own line in this format: "CONTROL VARIABLE - EXPLANATION OF HOW IT WILL BE CONTROLLED") Material of ball - same ball will be used each time Mass/volume of ball - same ball will be used each time Type of surface - same material/tile will be used for all trials Drop mechanism - dropped with minimal force (freefall) each time Temperature - Assumed constant in an enclosed classroom Camera position - will not change the position after the first recording Please list any equipment you would need to perform your investigation. Meter stick Phone/recording device/Loggerpro video analysis Rubber ball Hard surface/tile 2 Please provide a description of the investigation. Your description should be one to two paragraphs and should outline what you would like to investigate and how you plan on investigating it. Investigating how the color of a laser affects the critical angle of glass. I will get a few different monochromatic lasers, and shine them through a rectangular glass prism. I will also put a white screen (such as paper) a distance away from the prism, where the refracted light will leave, to see the movement of the light as I adjust the angle. I will also plan to use white light as the control. When I shine the white laser, the point at which there will be a critical angle will be when the light from the screen disappears, which I will then mark. I will then do the same for each color, and measure them based on their distance from where I marked the white light. Why is it interesting to you? In your response you should discuss a broader context than just "because I like it". The response should be more than one sentence/word. I saw images of glass prisms that could disperse white light into a rainbow, and found that interesting. I could see that each color’s wavelength had a small change in angle of refraction, and so I wanted to see if this also affects the critical angle of monochromatic light in this glass as well. State your independent variable. Color of laser Explain how you will measure and change your independent variable. I will use a white laser and three other monochromatic lasers of different colors. State your dependent variable. Distance between critical angle of the color and critical angle of white light (marked on the screen) Explain how you will measure your dependent variable. If it will be processed (calculated), you should include a brief description of the process I will measure with a ruler List any control variables AND FOR EACH ONE briefly explain HOW you will control it. (please format each one on it own line in this format: "CONTROL VARIABLE - EXPLANATION OF HOW IT WILL BE CONTROLLED") Position of prism and screen - Prism and screen will have a set distance apart Position of lasers to the prism - I will try to make a stand to keep the lasers in position when changing colors each time Shape/material of prism - Same prism will be used each time Type of laser - Same type of laser will be used for each color Temperature - Assumed constant in an enclosed classroom Please list any equipment you would need to perform your investigation. White and 3 other colors of lasers Rectangular glass prism White screen/paper Ruler Stand (to keep position of laser) 3 Please provide a description of the investigation. Your description should be one to two paragraphs and should outline what you would like to investigate and how you plan on investigating it. Dropping a ball from different heights on sand to see the change in size of the crater. I will have a meter stick propped up to measure the heights I will drop a ball from. At the bottom, I will have a container filled with some sand (possibly approx. 2 inches deep) for the ball to drop on. I will then use a ruler to measure the radius and diameter of the craters and repeat trials for each height. I will use the height of the ball to find its impact velocity through the conservation of energy (potential energy = kinetic energy). I will then graph the changes in impact velocity and kinetic energy against the radius/diameter of the crater to see whether either value has any correlation to the size of the crater. Why is it interesting to you? In your response you should discuss a broader context than just "because I like it". The response should be more than one sentence/word. I have been interested in astronomy since I had the astronomy unit in science class in grade 9. I wanted to see what factors affected the creation of craters on the moon from asteroids, and decided to make a very simplified version of this through the experiment. These craters also have impacts on land and geological structures, such as in the creation of landforms. State your independent variable. Height the ball is dropped at (m) Explain how you will measure and change your independent variable. Dropping the ball from different heights, measured by a meter stick State your dependent variable. Radius/diameter of crater (cm or m) Explain how you will measure your dependent variable. If it will be processed (calculated), you should include a brief description of the process It will be measured with a ruler List any control variables AND FOR EACH ONE briefly explain HOW you will control it. (please format each one on it own line in this format: "CONTROL VARIABLE - EXPLANATION OF HOW IT WILL BE CONTROLLED") Material of ball - same ball is used every trial Mass/volume of ball - same ball is used every trial Depth of sand - depth will be kept consistent at 2 inches deep Type of sand - same type of sand is used every trial Position of meter stick - meter stick will not be moved after the first trial Temperature - Assumed constant in an enclosed classroom Please list any equipment you would need to perform your investigation. Meter stick Sand Container for sand Ball Ruler https://physics.stackexchange.com/questions/93717/the-relationship-between-craterdiameter-and-the-velocity-of-an-object Should i try to derive this relationship in the background information and then compare it to my actual values, or should I graph my experiment values and then try to derive this relationship? Since this isnt an official site and im not sure if the relationship is actually true or not How could i derive a theoretical relationship between these two? Do i need to take into consideration energy dissipation and how that connects to area of crater or something? Also should I use sand or something else that holds its shape a bit more like flour? - - - - - - - - - - - - mgh=(½)mv^2 n=0.25 - Empirical Scaling Factor: how strongly the crater diameter depends on impact energy.(mgh, KE) - Granular(sand) 0.25 v=sqrt(2gh) KE impact = 1/2mv^2 = mgh Crater is proportional∝ Diameter is proportional to mgh^n d=kmgh^n D∝(mgh)^n D∝(KE)^n D∝v How does the height of ball dropped affect the diameter of crater formed in the sand?