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Name: Dropping a Bucket of Water - Demonstration Category: Circular Motion & Gravity Date Added: 2018-01-14 Submitter: Flipping Physics Demonstrating the physics of dropping a bucket of water with two holes in it. Want Lecture Notes? This is an AP Physics 1 topic. Content Times: 0:17 The physics of dropping a bucket of water with two holes in it 0:57 The demonstration 1:18 Why water stops flowing out of the holes 2:43 Why it takes half a second for water to stop flowing out of the holes Next Video: Apparent Weightlessness Introduction Multilingual? Please help translate Flipping Physics videos! Previous Video: Altitude of Geostationary Orbit (a special case of Geosynchronous Orbit) Please support me on Patreon! Thank you to Jonathan Everett, Christopher Becke, Frank Geshwind, and Scott Carter for being my Quality Control Team for this video. Thank you to Youssef Nasr for transcribing the English subtitles of this video. Dropping a Bucket of Water - Demonstration

Name: Minimum Speed for Water in a Bucket Revolving in a Vertical Circle Category: Rotational Motion Date Added: 2017-10-30 Submitter: Flipping Physics What is the minimum angular speed necessary to keep water in a vertically revolving bucket? The rope radius is 0.77 m. Want Lecture Notes? This is an AP Physics 1 topic. Content Times: 0:13 The demonstration 0:35 Understanding the problem 1:04 Where do we draw the Free Body Diagram 2:06 Summing the forces 3:04 What happens at the minimum angular speed 3:53 Why the force of tension is zero 4:41 Solving the problem Next Video: The Right Hand Rule for Angular Velocity and Angular Displacement Multilingual? Please help translate Flipping Physics videos! Previous Video: Analyzing Water in a Bucket Revolving in a Vertical Circle Please support me on Patreon! Thank you to Aarti Sangwan and Christopher Becke for being my Quality Control Team for this video. Minimum Speed for Water in a Bucket Revolving in a Vertical Circle

Name: Analyzing Water in a Bucket Revolving in a Vertical Circle Category: Rotational Motion Date Added: 2017-10-23 Submitter: Flipping Physics Analyzing the forces acting on a bucket of water which is revolving in a vertical circle. Want Lecture Notes? This is an AP Physics 1 topic. A big thank you to Mr. Becke for being a guest in today’s video! Content Times: 0:11 The demonstration 0:24 Drawing four Free Body Diagrams 1:30 Summing the forces with the bucket at the bottom 2:27 What is the centripetal force? 3:28 Why the Force Normal greater than the Force of Gravity with Mr. Becke! Next Video: Minimum Speed for Water in a Bucket Revolving in a Vertical Circle Multilingual? Please help translate Flipping Physics videos! Previous Video: Demonstrating Why Water Stays in a Bucket Revolving in a Vertical Circle Please support me on Patreon! Thank you to Aarti Sangwan and Christopher Becke for being my Quality Control Team for this video. Analyzing Water in a Bucket Revolving in a Vertical Circle

Name: Demonstrating Why Water Stays in a Bucket Revolving in a Vertical Circle Category: Rotational Motion Date Added: 2017-10-15 Submitter: Flipping Physics Yes, water stays in the bucket. Would you like to know why? Watch the video and learn! Want Lecture Notes? This is an AP Physics 1 topic. Content Times: 0:14 The demonstration 0:52 Why does water flow out of a bucket? 1:40 Inertia! 2:38 Visualizing why Next Video: Analyzing Water in a Bucket Revolving in a Vertical Circle Multilingual? Please help translate Flipping Physics videos! Previous Video: Determining the Force Normal on a Toy Car moving up a Curved Hill Please support me on Patreon! Thank you to Aarti Sangwan and Christopher Becke for being my Quality Control Team for this video. Demonstrating Why Water Stays in a Bucket Revolving in a Vertical Circle

Name: Impulse Comparison of Three Different Demonstrations Category: Momentum and Collisions Date Added: 2017-02-09 Submitter: Flipping Physics A racquetball is dropped on to three different substances from the same height above each: water, soil, and wood. Rank the _______ during the collision with each substance in order from least to most. (a) Impulse. (b) Average Force of Impact. (Assume the racquetball stops during the collision with the water and soil.) This is an AP Physics 1 Topic. Want Lecture Notes? Content Times: 0:11 Prom Dress Day! 0:20 The three demonstrations 0:32 The problem 1:43 The equation for Impulse and Impact Force 2:02 Understanding the two parts to the demonstrations 3:33 Part (a): Impulse [water and soil] 4:47 Part (a): Impulse [wood] 5:23 Part (b): Impact Force [water and soil] 6:27 Part (b): Impact Force [wood] 7:59 The Ann Arbor Prom Dress Project Thank you to Jan Wery and Judi Lintott of the Ann Arbor Prom Dress Project: “Find your dream dress for less than $25." Next Video: Review of Mechanical Energy and Momentum Equations and When To Use Them! Multilingual? Please help translate Flipping Physics videos! Previous Video: Using Impulse to Calculate Initial Height Please support me on Patreon! Thank you to my Quality Control help: Scott Carter and Jennifer Larsen Impulse Comparison of Three Different Demonstrations

Ever since I heard about this blogging assignment, this was the first idea to come to mind. I used to play the game Super Mario Sunshine frequently in my childhood. The game stars Mario in a tropical setting, using a water-fueled jetpack to hover over large gaps for a few seconds. Using this jetpack, he can hover over characters and spray water on them to clean them off. Sounds harmless enough, but I wanted to see just how powerful this water pack could be. Many have assumed that Mario weighs somewhere around 165 pounds, so I will be using this for my calculations. Converting this to kilograms, we get 74.8427 kg. In order to calculate the force needed to hold Mario in place in the air, we need the force exerted by gravity on Mario. Using the equation Force = Mass * Acceleration, we can plug in the numbers 74.8427 kg for mass, and 9.81 m/s2 for acceleration due to gravity. This gives us a force of 734.206887 Newtons of force. In order to compare this device to something realistic, we need to determine its pressure. One way of doing this would be to find its PSI, or Pound-force per Square Inch. Since we have an answer in newtons, we can convert this to PSI using a different value for pressure, Newtons per Square Meter. This requires us to find the area of the water stream. Assuming that the stream of water is perfectly circular, and that its diameter is equal to the diameter of the nozzle at its widest point, all we need is the area of the nozzle. To do this, I can measure based on an actual model taken directly from the game's files. Doing this, I compared the backpack to Mario's official height of 5'1", and scaled it accordingly. Then, I measured the nozzle's diameter, and got a measurement of 30 centimeters. Using the equation Area = Pi * Radius2, substituting in .15 m for radius, we get an area of .070686 m2. The pressure unit is Newtons per Meter Squared, so dividing 734.206887 N by .070686 m2 will give us a pressure we can convert to PSI. This gives us 10386.90269 N/m2. Converting this to PSI gives us...1.5 PSI. This seems pretty underwhelming. For comparison, some garden hoses are rated for maximum PSIs of 150. Did I do something wrong? That's about all the time I have for now. Let me know what you think, and if there are any ways I could improve or simplify my calculations! For now, I'll leave you a video of a real-life water jetpack. See you next time!

A few days ago scientists confirmed that there is liquid water on Enceladus one of Saturn's 53 or so moons. The surface of Enceladus is covered in a thick sheet of ice but NASA's Cassini spacecraft which has been orbiting Saturn since 2004 has sent back images of geysers of ice, water vapor and organic compounds shooting out from cracks in the ice at the south pole of Enceladus. This was the first sign that there may be liquid water below the ice. Also, NASA noticed slight changes in Cassini's trajectory and the wavelength of it's radio signals which suggested that Enceladus has a greater mass at the south pole. In addition, it has long been known that Enceladus is flatter at the south pole than anywhere else. The best explanation for both phenomena is that there exists a large body of liquid water, which is both denser and has less volume than ice, underneath the south pole. This subterranean ocean is estimated to be about the size of lake superior and is particularly exciting because it is thought to sit above a layer of rock that could provide chemical reactions which when coupled with the organic molecules in the geysers could possibly produce simple organisms. Unfortunately Cassini doesn't have the instruments needed to properly test the makeup of the molecules in the geysers and the ice above the lake on Enceladus is somewhere around 20 miles thick so a much more sophisticated robot would need to be sent in order to search for life. Below are a Cassini picture of the ice plumes at the south pole and a rendering of Enceladus's cross section.

This blog was inspired by this fact: The New York City water supply system leaks at a rate of up to 36 million US gallons (140,000 m^3) per day. Source: http://www.nytimes.com/2008/11/23/nyregion/23tunnel.html?pagewanted=2&_r=0 Our water is extensively purified, and is completely safe to drink, but how can it be safe if some of the biggest supply pipes have holes all over? Besides the full -on sanitation of the water, one part of the solution is that our water supply contains some residual chlorine and other chemicals that stop bacteria growth from occurring in tap water. Any pipe leaks/breaks that occur in supply lines that can actually affect water quality can be isolated and the water diverted until a replacement segment is installed. also, the pipes are pressurized to a level where nothing could get into the system through a hole because of the pressure difference. This is visualized by seeing water leak OUT of a pipe, and not seeing things go in. By the way, tap water is safer than bottled water and is subject to stricter regulations in many different tests.

Water is strange. Unlike most compounds, its solid form is (normally) less dense, and of a larger volume than its liquid form. Because of this, its very difficult to compress water, because normally there isn't really anything to compress it into. But the story of ice is a bit different from the snow and hail we see falling outside of our windows during these winter months. In fact, ice has many different forms, depending on the conditions it forms in. The ice we commonly know is called Ih - a common ice type with a hexagonal structure. But as you can see from the picture, there are many different types of ice. Ic is also a (relatively speaking) common ice type, with a cubic structure that can be present in the upper atmosphere. In total there are 15 different types of ice, all forming at different pressures and temperatures, all with different crystal structures, densities, and electrical properties. For example, while water is hard to compress, when put under great enough pressure at normal temperatures, can form into ice IV (not pictured), a denser form of ice. While most variations are just density and structure based, certain forms (like ice XI) have ferroelectric properties, which is something I looked up and failed to understand, but it sounded interesting. And noticing the lower pressures, below ~1 kPa (about 1/100 of normal sea pressure), liquid water fails to exist, and water vapour will undergo deposition straight into ice below this point. As we head into winter, it's interesting to note the complexities of such a common substance. It can take on many forms with many properties, and I think that's pretty cool.

Have you ever been doing chores or showering and wondered how the water comes out of the shower head or faucet? Well, if you have, this blog entry will explain the basics of how they work. A faucet is a device that regulates the flow of water in a system, such as a house or school, and without them, water would be flowing constantly out of pipes be almost useless in everyday life. SImple machines work to control the pressure and flow of water, including levers and screws. The pressure inside of water pipes is much higher than the pressure of the air outside of the tube, which allows the water to flow up from the ground, against the force of gravity, and out into the kitchen sink. However, in the way, are small openings and valves, such as check valves, which do not allow the flow of water back past the valve. This keeps the water flowing at a normal pace, only to be blocked by more valves, like the ones in faucets, which must be manually turned to allow the flow of water, from hot and cold pipes. Next time you use your shower or wash the dishes, remember the physics and engineering principles of the flow of water, and how all that work is done just to clean your hair or a glass from lunch.