Fluid pressure problems?
Fluid Mechanics: Pressure Problems 1. In a certain gasoline engine, the ignited gasoline and air mixture in a single cylinder exert a pressure of 1.50 × 106 Pa on the upper surface of the piston. If the force exerted by the gas on the piston is 1.22 × 104 N, how large is the area on the piston’s upper surface? 2. The two Echo satellites, which were launched in 1960 and 1964, were early examples of communications satellites. The Echo satellites consisted of aluminum-coated Mylar balloons that reflected radio signals from one point on Earth to another location on Earth’s surface. Suppose the gas pressure inside Echo 1 was the same as the atmospheric pressure at Earth’s surface. If the total force exerted on the inner surface of Echo 1 was 2.86 × 108 N, what was the surface area of the satellite? Given that the surface area of a sphere is 4pr2, what was the radius of the satellite? 3. A ball strikes the pavement with a force of 5.0 N. If the pressure exerted on the pavement is 9.6×103 Pa, what is the area of contact between the ball and the pavement? 4. A hydraulic lift consists of a piston, on which is placed an automobile with a mass of 1.40 × 103 kg. The other piston consists of a block of ice with a uniform thickness of 0.076 m. Given that the density of ice is 917 kg/m3, what is the area of the piston holding the automobile? Assume that the weight of the automobile is uniformly distributed over the piston’s surface. Assume the piston to be massless. 5. A door with an airtight fit around its edge has an area of 1.54 m2. Suppose the pressure on the inside of the door is 1.00 percent greater than the pressure on the other side of the door. If the outside pressure is 1.013 × 105 Pa, how large a force must you exert on the door to pull it open? How large a mass can just be lifted by this force?
Congestive Heart Failure?
My sweet hubby has lived with heart failure for around 23 years. 2 years ago when he was in I.C.U. (3 heart attacks in 17 hours WITH pneumonia) Docs. said he had less than a10% chance to survive. This morning he was out raking the lawn...cleaning the garage out. We have done everything we can to make the proper choices for a long & happy life. It all depends on the general health & mind set of the person. There is no set answer.
I work on the computer all day. My back/neck always hurts. What action should I take?
Answering because I had the same problem and I fixed it very quickly (around 1-2 months).It's already been mentioned below, but worth repeating: strength training. At the end of the day your body can't handle what you're throwing at it, which is having to sit in a position that exerts your back and neck muscle all day. The simple solution is to make your muscles stronger so they don't get tired as quickly and you have no more soreness.I had back aches for the first few years of my work life, and I tried many things like new chairs, putting the computer higher, the beach ball thing etc. My mother, a former competitive swimmer, insisted that I try swimming. I changed my diet. Tried going on walks during the day. Toyed with the idea of a standing desk, gave up after seeing everybody who tried go back to a chair within a few weeks. Nothing really worked.I chatted about it casually with a friend who is a former US Marine, and has been working as a fitness trainer for a decade with a variety of clients. He told me he heard this all the time and that it was because I was weak, and I should try strength training. On his advice, I took up high intensity training (basically, do very few reps, to muscular failure, once a week to stimulate growth) and within a month or two, my back pain was gone. It was just good old muscular weakness. It's been gone for years and I don't miss it. I can sit in any chair, which is good because the last two offices I've worked in have terrible chairs. I can crouch on my laptop for hours, which is good because I've gone from 4 vertical screens to a Macbook Pro Retina 13".So... hit the gym (preferably a cheap one in the suburbs with no treadmill, no music and some heavy slightly rusty weights), do some heavy deadlifts, pulldowns/weighted pullups, try and increase the weight 5% a week, see if it fixes the problem.
What will happen if I leave my phone in the freezer overnight?
I did this once by accident. Not overnight but for about 3 hours.I have an Exynos powered Galaxy S7 edge and anyone who uses this phone knows that once the phone is used with the Gear VR it essentially turns into burning coal. The metal chassis would be too hot for comfort at about 50°C. It never bothered me since I would simply put my phone in the fridge for about 15 minutes or in the freezer for 2 minutes and everything would be normal.So one find morning after a game of PokerVR, I noticed the phone was hot and I put it into the freezer and got occupied with other stuff. Totally forgot about the phone. 3 hours in I noticed I don't have my phone. I started searching for it but couldn't find it anywhere. After about 5 minutes I decided to try calling it and listen to it ring. I did so and I could hear a faint ring. I thought maybe it's under my blankets on the bed or stuffed in the sofa but I couldn't find it and thats when it struck me. I ran to the fridge and took out my phone. I noticed the temperature on the freezer was displayed at -8°C. To describe the condition of my phone, a thin layer of ice maybe 2mm thick had formed around the entire phone. As soon as I touched any part of the phone the ice would just start to melt. Although the phone rang when I had called it was unresponsive now. I thought I surely damaged some contact point for the display. I got a bowl of warm water and immersed the phone into it. Waited a couple of seconds and tried to turn it on. It showed battery low indicator which was surprising because I was sure I had about 80% of charge before putting it into the freezer.I decided to set the phone aside and see what happens. After 10 minutes I blew into the USB port to remove excess water and put it for charging. It charged to about 20% and then I turned the phone on. It was laggy as thought it was trying to run some advanced tech on 2001 hardware. After a few minutes it stabilized and started working properly.A year has passed since that incident and no issues what so ever.
When we want to set up a water tank, why do we put it higher than our house?
its a little thing called gravity http://en.wikipedia.org/wiki/Water_tower