A head is the part of an organism which usually includes the ears, brain, forehead, cheeks, chin, eyes, nose, and mouth, each of which aid in various sensory functions such as sight, hearing, smell, and taste, respectively. Some very simple animals may not have a head, but many bilaterally symmetric forms do, regardless of size.
Heads develop in animals by an evolutionary trend known as cephalization. In bilaterally symmetrical animals, nervous tissues concentrate at the anterior region, forming structures responsible for information processing. Through biological evolution, sense organs and feeding structures also concentrate into the anterior region; these collectively form the head.
The shaver head in the Beurer HR 8000 (rotary) is supposed to be detachable, so you can swap it with a supplied alternate accessory. But try as I might, I just could't take it off. Does anyone have this model, and have they managed to detach the head?
This guy seems to have to struggle a bit...
I have a question that is bothering me. It is commonly accepted that when playing heads or tails with a fair coin and a large number of tosses are made, the probabilities of getting heads or tails are equal to 50% for each toss. However, the principle of determinism, which states that under the...
A vacuum pump is mounted at ground level. The pump is connected to a tree of overhead pipework at a height of 20ft, connected to the pipework are 12 hose reels that can be attached to oil drain tanks. The client requests that the pump be sized so that sufficient vacuum can be achieved to suck...
I am trying to mathematically prove the Static Pressure Head equation:
H = p/ρg
How can I prove this equation and thus determine the nature of the relationship between these variables?
Hi,
I was watching a video where the following formula, for expected value, was presented for a discrete probability distribution which cannot take negative values:
E[X] = \sum_{j = 1}^{\infty} P(X \geq j)
and I never saw this formula before and am trying to develop an intuition for it. I am...
A pump’s power is a product of its pressure rise times volume flow rate. Commonly, a pump is specified by giving the pressure rise, or head, it can provide and the flow rate, such as in gallons per minute(GPM).
But some pumps provide the user with a chart that shows how the pressure rise can...
NY Times article here.
Two species of sea slug (like a snail without a shell) have been shown to be able to amputate their bodies from their heads and then regenerate the body.
It is hypothesized that this is done to rid themselves of internal parasites.
I am trying to calculate head loss for a sloped pipe.
I found this calculation here, which seems to be what I want..or at least a start:
https://www.pumpsandsystems.com/pumps/april-2015-calculating-head-loss-pipeline
My confusion/skepticism arises from the fact that the equations in the above...
Hey everyone - I run a music school and learning about how sound works is really helpful in talking about tone production, volume, and just understanding in general what's going on. As part of that,. I'm looking for a pattern that I could print on a drum head that would show how the head moves...
I am scratching my head on the problem but cannot figure out what to do. I tried in the following way:-
For (9)
_ _ _ _ _ . The middle place is fixed means only 1 way there. For the first place 9 ways (excluding 0) , second place (9 ways again because 9 digits are left excluding 9 and 0). Third...
i've this question that i can't seem to work out an answer.
supposing that a (centrifuge) pump transfer an amount of energy (power) p to a column of water height h so that it maintains that as a static head. i.e. the water level in that tube is at a fixed height h due to the power transferred...
Hi All, I considered filing a patent for this invention, but instead decided to publish it so people could use it to advance the state-of-the-art in drums.
You don't need to add tape or pillows to your drum heads to muffle the overtones. Using tape or pillows also kills the strike of the...
I have long found myself turning my head fairly quickly when a noise steps on something I'm trying to hear. Sometimes it is just a noise like a bang or a pop that steps on a conversation I'm listening to, and sometimes it will happen when another person starts to speak and interferes with a...
Say that these pictures are accurate.
Personally, I think I can solve this problem, but the issue is, that I had a debate on it with my Physics teacher.
This is how my teacher would solve it; my teacher says that each Fk on each side is constructed from half of F and Fx. So, F = 2 * Fk * sin...
Hi,
I just hit my head on the top of my car door as I was leaving my car; the hit hurt my head a lot and I am worried that I received a concussion. However, I read that most concussions require more than 65 Gs of force to be classified a concussion which is why I am wondering if someone here...
Hi,
I have a rainwater collection system where we have to pump water to the main cistern during a rain event. The system works great the way I have designed it and the rainwater is awesome to use in the house and water the plants and grass. The length of pipe I pump the water is almost 300...
The researchers associated with this bird claim it has different dance moves,and that the bird has innovated new dance moves over time.
The video is halfway down the article, if you want to cut to the chase...
See attached image
I experienced yesterday that when the slotted screw driver head was exact fit to the slotted screw, it was easier to turn the screw into the hard wood. I'd like to understand the physics of it.
Is the bottom (in the picture) easier to turn because there is even contact...
I am not really worried about the numbers, but more about the simple concepts with head loss in these pipe flow questions. I want to confirm that head loss just means the change in static head, right?
I have been advised that for a problem like this, it is nothing more than the conservation of...
Let's keep things simple. I have pure water. pH = 7.
I want to add a buffer. I add the weak acid. It dissociates little. So the pH is still close to neutral. So far so good.
The problem is, we are also adding conjugate base (the conjugate base is strong). Why doesn't the added base consume the...
I have looked all over the net and can only find descriptions of how to use a dividing head, followed by countless numerical examples. There must be someone on PF who can give a short algebraic description of the way they work. Machinists as a whole, don't seem to want to present the topic in a...
Hello!
1. Homework Statement
Symbols and variables:
##\dot{V}## : flow rate
##H## : Hydraulic head
##g = 9.81 \frac{N}{kg}##
##P_{atmosphere} = 101325Pa##
##\rho = 1000\frac{kg}{m^3}##
I am given a piping system, with serie and parallel pipes, they start from one point and go back into one...
Hi, I am here again. Sorry if this thread is not that related here in this field. I just want to ask, if I have to build a micro hydropower scheme in a wastewater of a hotel, what net head is suitable to use? (Sorry, I can't construct a clear sentence).
No, I didn't climb a statue. :-p I drove up to Asheville NC today via a slow route and stopped at Caesars Head State Park just before crossing the state line.
180° panorama from the overlook:
Hello,
The explanation for this, min 0:54
is that you have Fe2O3 in the match head, and after burning it, pure iron is obtained
2 Fe2O3 + 3 C -> 2 Fe + 3 CO2
I think the chemical explanation is fine, but I don't understand why Fe2O3 is added (as colorant, if the red phosphorus is already...
Hi all,
Quick question:
What do you guys use as your reference for minor head loss coefficients (k).
I'm sure those with more experience have their own database/excels of k values found over the years. I have been personally using a combination of my Hydraulic Engineering Textbook and Google...
Translation: A man with a mental illness tried to kill himself with a shot in the head. Instead of dying, the bullet struck the part of the brain that caused the mental disorder; he healed and became a great student in college.
I know that the page is not there these things. But I have a...
Hi. So I've got an essay I have to write on sports equipment and how they increase safety. I know that in football, equipment to increase safety includes helmets, shoulder pads or paddings and cleats. Unfortunately, I have no idea how each of those equipment work to increase safety.
Okay, let's...
Hello,
I have the following hot water system. I have a water heater with a pressurized cold water inlet. A re circulation line is taken near the farthest fixture passed through a circulating pump and back to the heater inlet. When calculating pump head, do I calculate pressure drop in the entire...
Hey! :o
A fair coin is tossed $ n $ times; $ X_i = 1 $ denotes the event that "head" appears in the $ i $-th toss.
a) How are the single toss $X_i$, $=1, \ldots , n$, distributed?
b) How many toss are needed so that the proportion of "head" $\overline{X}_n$ is in the interval $0, 45 <...
for those Who Dont know golf. Swing weight is a measurment how Heavy the clubhead Feels. If i put on a heavier grip the swingweight falls. Heavier head swing weight goes up etc.
If i Want to swing the
Club with as little clubhead rotation as possible (i know forarm creats the rotation) Would i...
Homework Statement
When a soccer ball is kicked toward a player and the player deflects the ball by "heading" it, the acceleration of the head during the collision can be significant. Figure 2-38 gives the measured acceleration a(t) of a soccer player's head for a bare head and a helmeted head...
Hello! In an experiment (I don't have the details) the predicted head loss in a circuit of pump and pipes was higher as the flow rate increased, than the actual head loss (pressure differential). Can you tell me please what could result in that? What systematically acting factor created an...
Hi All,
My question is about bulb turbines and head.
Bulb turbines are used for tidal energy.
I guess the inlet and the outlet of the turbine (or the pipe where the turbine is mounted) are both under water.
Is head the difference in height between the water surface at the inlet and the water...
Hi, I have this problem:
I have a vertical tube 1 meter D, in the bottom end there is a nozzle with 0,5 m D. The tube is full of water. the tube length is 10 meters and the nozzle length is 2 meters. I need to calculate the power of this by this equation:
W = Q * g * h * p
where W is watt, Q...
I previously posted this question on this website:https://math.stackexchange.com/questions/2297129/shower-head-jet-separation
However, I'm not sure if the answers I got were correct or the answers that I found out were correct, or if neither of them were.
Can anyone help assure me which one is...
Hello
I have to do an nmr experiement. Why do i need a broadband probe head? I have a magnet with 2 tesla. and modulation coils on it with a frequency of 50hz. For example i have a resonance frequency at 50mhz.
i hope you can pelp me.
a boat A is heading south at 30 km/hr. its spotted a boat B which is 18 km due east of boat A. boat B has a max speed of 25 km/hr and wishes to get a close as possible to boat A. what direction should boat B head in.
so i initially let boat A be the origin heading south. boat B starts at (18,0)...
I have a centrifugal pump 50 m above a vessel, I’m pumping water in at 4 bar gauge into this vessel. I then close a valve to cease pumping ensuring no air enters the system.My question is, if I now open that same valve to atmospheric air this time, will the water exit from the pipe through the...
Homework Statement
Hello there physicsforums,
I have a problem that I'd like feedback on as I'm not sure if I had solved it or approached it correctly.
A ball that is traveling 5m/s is 30 meters above a person who is standing still. How fast must the person travel in order to catch the ball...
Homework Statement
Calculate the diameter of a baby's head if there is a time delay of 96 microseconds between receiving pluses from either side of the skull and the speed of ultrasound can be assumed to be 1250m/s.
Homework EquationsThe Attempt at a Solution
The diameter of the baby’s head...
I was wondering why the head has it's own inertia during whiplash when the person is rear ended by another car?
I thought that the head would be moving forward also because it is part of the system of the chair being impacted to move forward?
Homework Statement
In a low-flow showerhead that contains 18 nozzle holes, the volume flow rate of the water is 4.00 L/min and the water maximum speed is 2.70 m/s.
What is the diameter of each hole? Do not ignore viscosity of water.
Homework Equations
Q=Av_max
Q=((pi)r^2)v_max...
A coin is tossed 4 times.
Is there a way to determine mathematically what is the probability that exactly 2 heads occur?
By drawing a decision tree I can determine that it is 6/16, but this seems like an arduous process for larger numbers.
I have an above-ground pool which, tis the season for draining and winterizing. I have a 15 foot section of ribbed pool hose (designed for pumping) that I hook up to the pump and flush the pool with.
Pool is 4 feet deep both inside and outside, with a 1foot lip.
Hose needs to rise one foot...
Is due to a collision between the head of the 20-man wall at the swimming pool can crack the back of the pool as in the following picture?
Professional anyone who knows the man's skull and pool tiles?
I just swam back and crashed against the pool with his head, and since I'm in pain and cervical...