Underwater Definition and 154 Threads

Why is there better visibilty when viewing under water through a glass bottom of a boat rather than say looking over the side of the boat?

For this engineering project I am trying to understand how the pressure would be distributed (if at all) throughout the enclosure. It will be at a depth of 500 meters (4888 kPA). It is designed with a stainless steel enclosure which can withstand the external pressure at this depth. Inside is...

Imagine there is a square plate fixed at the edge on all sides, it is impacted by a body with a pre-determined kinetic energy. Now assume that this plate is submerged in water and impacted by an identical body with the same amount of kinetic energy. Will the results be different? How to...

Like many I’ve been captivated by the Titan story. I’m wondering a few things: 1. Was a shock wave cause by the implosion? 2. Would marine life have been killed similarly to “fishing w/ dynamite”? Kill radius? 3. A TV talking head claimed the inside of the vessel would have heated to “a temp...

For this problem, The solution is, I agree with their solution from Archimedes principle, however, if I look at the equation ##PA = F##, where ##A = 4\pi r^2## and ##F## is the force over the entire apple assuming it is spherical. I thought the pressure will increase with depth and therefore I...

https://www.cbsnews.com/news/vanuatu-underwater-volcano-erupts-east-epi-warnings/ The volcano lies 68 kilometers north of the capital Port Vila.https://volcano.si.edu/showreport.cfm?wvar=GVP.WVAR20230125-257060

I've been trying to pick up the fundamentals of electromagnetic theory and I reckon I'm doing alright, but I've run into a some questions about how magnetic fields behave in an anisotropic fluid medium like the ocean. There is an awful lot of conflicting information online. Ultimately, I'd like...

I would know how to solve this problem if the person had been standing pratically above of the object underwater by using Snell's law and the approximation ##\sin(\theta)\approx\tan(\theta)## fopr ##\theta## small, but in this case I don't see how to find the angles ##\theta_1## and ##\theta_2##...

Hi all I have acoustic noise level value in dB vs 1 dyne/sq cm e.g. -10 db vs 1 dyne / sq cm. I need to convert it into dB ref 1upa unit. How i will convert it? Thanks & Regards

Using the data given and recalling that in this configuration ##R<0## I get: ##\frac{1.33}{0.5}+\frac{1.5}{q}=\frac{1.5-1.33}{-0.2}\Rightarrow q\approx -0.427 m=-42.7 cm## so the image is virtual and is ##42.7\ cm## to the left of vertex ##V##. The magnification is ##M=\frac{n_1 q}{n_2...

Hello, Something I’ve wondered about is those amazing air bubbles that are sometimes found in underwater caves. In particular, I was wondering how the depth of the water does or does not affects them. In my Figure 1 example, the water is 50 feet deep and air bubble in the cave has 3 feet of...

https://www.bbc.com/news/science-environment-57382529 5 m/s is about the speed of cooling water in the core of a PWR. It's not very fast, 16.4 ft/s, or 11.2 mph.

Hi all I am trying to calculate Source Level 'SL' of a underwater acoustic Cylindrical Array with multiple Transducers. The array has 03 Rings with 32 transducers in each Ring. The spacing between each ring is around 0.18m whereas Dia of each Ring is about 1m. Each transducer is being driven...

I figured out that the pressure is 8.0442x10^7 Pa and I’m not sure how to approach the second half of the question. I’m thinking I use the formula F=PA but I’m realizing it’s not saying that .15m is a diameter or a radius.

I finally saw Ford v Ferrari, and one of the shorts opened with a team of people working seven miles under the ocean. My immediate, very excited, thought was that they've made Peter Watts amazing novel, Starfish, into a film. Starfish is the first in Watts' Rifters trilogy, and I loved it...

Summary: I am not a physics student but I really need to prove that aluminium will not deform 10m underwater Hi I am doing a project of a product which will sink underwater. It will be a sealed cylindrical vessel, length 2m, width 1m, thickness 0.02m. Aluminium 6061t will be used with a yield...

I'm trying to determine the force needed for one object to displace another object underwater. Specifically, Object A strikes Object B hard enough to jettison it from the seafloor up to sea level/land, let's say the Pacific coastline. I have a timeframe in mind, density & mass of the two...

Is there any formula for underwater falling sphere which can measure the velocity of that sphere at any time before it reaches its terminal velocity? A sample question is: I dropped a sphere into water with 0m/s initial velocity. what will be the velocity of that sphere after 3s? {the radius and...

Hi, I'm trying to model the transmission loss and SNR of an acoustic signal underwater. I'm using this expression to modelize the transmitted signal: y = sqrt(P)*exp(1i*2*fr*pi*t)' where P is the transmission power in watts, fr is the transmission frequency and t is the acquisition time. The...

Homework Statement A scientist investigating the movements of dolphins in the Mediterranean uses a dart gun to shoot small, harmless tracking devices onto the fins of dolphins. When standing on deck, her hand is 1m above the water, and looking along the dart gun she is holding at an angle of...

Homework Statement The sound source of a ship’s sonar system operates at a frequency of 18.0 kHz. The speed of sound in water (assumed to be at a uniform 20°C) is 1482 m/s. What is the difference in frequency between the directly radiated waves and the waves reflected from a whale traveling...

So I am in high school, so I am not the smartest. That is why I have came here. I was on Kickstarter and saw a underwater drone and I got to thinking, what if we could breathe underwater. So obviously we can't take oxygen from H2O, so what if I made a giant vape type machine? What happens if you...

Can anyone assist. I'm workingg on a project for the installation of an underwater artwork sculpture. How do I calculate the tidal force on the structure to stop it moving on the seafloor. It's not anchored to the seafloor only sitting on it. Also what safety factor should be built into it for...

Hi all, I have some problems to understand how to calculate the transmission loss at long distance, which model do I have to use? I was looking into the energy flux model (Weston model), but I didn't understand at what range I should switch from "mode stripping" to "single mode". I am working...

Hello! I have a system depicted below. I need to know what is the working equation that governs the transmit and receive power of the transmitter and receiver in the diagram. The transmitted signal is a sound wave and not an RF signal, the transmission is underwater. I would like to know what is...

Hi, I have an underwater monitor housing made out of carbon fiber and an acryllic Glass on the other side. Over time the monitor heats up. I guess carbon fiber is a bad heat conductor :(. the Acryllic glass is almost 1cm thick. Does anybody have an advice on how to cool something like this...

Homework Statement You have a hemisphere, like half a ping pong ball for example, sitting in a cup under a few centimeters of water. The hemisphere is sealed to the bottom so that no water can get underneath it. What is the buoyant force the hemisphere experiences? Homework Equations P = P0 +...

How to make changing depths irrelevant for breathing in a small submarine or other manned underwater vehicle; in terms of the under breathing apparatus or system ?

Hi guys! I have question regarding vacuum and underwater pressure if anyone here could help me out with it. I'm not really a physics person (my math skills suck too much, lol), but I do find it very interesting. I recently bought some breathable stockingfoot fly fishing waders and whenever I...

I'm wondering whether it's possible to survive most fires by filling the bath with water and a balloon with air (it doesn't matter if it comes from human exhalation), then go underwater and breath through the balloon. When I was a kid I used to breath in a balloon that I would fill with air by...

Specifically, how deep can an enclosed space of a polycarbonate (I'm thinking about strong plastics) material withstand underwater before cracking and breaking. Say a 2 liter bottle

Hi guys, I am trying to build a underwater camera system with lights. The depth requirement is 1500 feet. I need to view the bottom well enough to understand what conditions exist. I need to know if the bottom is rock or sand or mud. I have solved the camera issue...well I think...lol The...

Can water inside a submersible object be pumped outwards to provide an acceleration while underwater?

For a given submersible object that has 360 directional maneuverability, what would be an ideal shape for that object? Sphere? **360 degree directional maneuverability meaning jets strategically placed around the object for propulsion, without rotating the object

I was wondering if sound underwater traveled further than sound in air? It seems like it wouldn't do to viscosity. I know that it travels faster however. Lastly, is the online reasoning for why we can't hear sound as well underwater correct: the water vibration bypasses some of the sensory...

Hi, I am trying to create a device that would "simply" make a bubble under the water. What I am aiming for is production of small bubble but continuously and under the water. When I say continuously, it doeant have to be for extended periods of time, could be just for ~2 hours but the longer...

Homework Statement 2 & 3. The Attempt at a Solution I've worked out: The total force on the gate. I have worked out the centre of pressure which I got a value of 10/3m (from the hinge). For the moment about the hinge I got a value of 981,000Nm using the equation M=FN*X where X is the centre...

Both involve water resistance, buoyancy, and density of water and air. Therefore, I would expect that the lift up of your foot would be easy but putting your foot down would be the most difficult. Lifting an object is easier bc of buoyancy force. Although, apart the object must be buoyant...

Hi, I have a waterproof smartphone with sensors like barometer, gyro, accelerometer, microphone). I want to do an app that 1) detects that the phone is underwater: I though in using some reading from touch panel as water is electro conductive and it may provide me some reading to indicate...

Homework Statement hey I am trying to work out the problem: If I shoot an ak47 underwater with 7.62x39mm ammunition, how far will the bullet travel before coming to a stop? Homework Equations The equation that I have used to find the drag force is the drag equation: F =1/2 p*A*C_d*v^2...

Hi, I was thinking if maximum light intensity underwater during seasons changes somehow. I firstly thought about considering monthly solar irradiance (http://neo.sci.gsfc.nasa.gov/view.php?datasetId=CERES_INSOL_M) however I thought this would have been biased at certain latitudes due to...

I have a physics homework question that i need help with; A submerged ball of negligible mass is attached to the bottom of a swimming pool by two strings as shown. The volume of the ball is 5000cm^3. Calculate the tension in each string. (hint you need to look up the density of water) How do i...

will an aluminum tube 127mm in diameter, 3.5mm wall thickness, enclosed on either end by 12mm thick disks with o-rings be able to with stand 15bar of pressure. Its for an underwater camera housing.

Hello all- First post. I am curious if it is possible to create cavitation underwater with these specific criteria. I am basically using a venturi device that will be pulled underwater in saltwater. Is it possible to get the vapor pressure down low enough to boil water (make bubbles). I have...

Hello, I am very much interested to how frequency of sound varies in water. Also, how the frequency varies with temperature and depth? What are the different formulas related to this? Secondly, how can we determine the best frequency of operation? I would be very thankful if anyone could answer...

Hi guys I was wondering of someone on here could briefly enlighten me on the chemical reactions that would occur with a Teflon Coated high carbon steel hook and a lead sinker while underwater? I am looking into the signals that may or may not be given off by these items both separately and with...

Hi all, Is sound amplified underwater? My reasoning is if a sound is louder underwater than it is on land, then it has been amplified. Is this correct?

Hello, I am trying to calculate the equivalent amount of weight that a submarine would be under at 1000m below the sea. Apologies if this isn't that well explained! At 1000m - 101 atmospheres - which is 14.5 psi per atmosphere - so at 1000m it would be 1464.5 psi. Do I then multiple 1464.5 by...

< Mentor Note -- OP has been reminded to use the HH Template and show their work in future posts... > A man fires a bullet into a swimming pool. There is a distance of 6m from the gun to the bottom of the pool. Does the bullet have enough force through the water to break an average bike chain...

Does anyone know a simple formula to calculate the acceleration of gravity underwater?