Surface tension is the tendency of liquid surfaces at rest to shrink into the minimum surface area possible. Surface tension is what allows heavier than water i.e., denser than water objects such as razor blades, insects (e.g. water striders), to float and slide on a water surface without becoming even partly submerged.
At liquid–air interfaces, surface tension results from the greater attraction of liquid molecules to each other (due to cohesion) than to the molecules in the air (due to adhesion).There are two primary mechanisms in play. One is an inward force on the surface molecules causing the liquid to contract. Second is a tangential force parallel to the surface of the liquid. This tangential force (per unit length) is generally referred to as the surface tension. The net effect is the liquid behaves as if its surface were covered with a stretched elastic membrane. But this analogy must not be taken too far as the tension in an elastic membrane is dependent on the amount of deformation of the membrane while surface tension is an inherent property of the liquid–air or liquid–vapour interface.Because of the relatively high attraction of water molecules to each other through a web of hydrogen bonds, water has a higher surface tension (72.8 millinewtons (mN) per meter at 20 °C) than most other liquids. Surface tension is an important factor in the phenomenon of capillarity.
Surface tension has the dimension of force per unit length, or of energy per unit area. The two are equivalent, but when referring to energy per unit of area, it is common to use the term surface energy, which is a more general term in the sense that it applies also to solids.
In materials science, surface tension is used for either surface stress or surface energy.
a)Determine the slowest speed that the keys can swing and still maintain a circular path.
Fnet = Fg + Ft
Fc = Fg + Ft
When Ft = 0, Fc = Fg
So, Fc = mv^2 / r and Fg = mg
mv^2/r = mg
v = √gr
v = √9.81 * 0.25
v = 1.56 m/s
Therefore, the slowest speed that the keys can swing and still maintain...
Helicopter lift weight of 500kg ,weight is connect with load cell to meassure tension.
Neglect aerodynamic drag..
If helicopter accelarate up ,tension is rope is greater than 500kg.
If helicpter accelarate down ,tension is rope is less than 500kg.
If helicopter fly up with constant speed...
First I determined the direction the masses will be traveling by comparing the change in potential energy, so when M2 rises by Δy, M1 drops by Δy. Potential energy decreases when M1 drops and M2 goes up.
Tension force for string pulling against M1= 400 x gsin30°, and since there are two strings...
Hi,
I'm being asked to determine the tension of a rope only knowing that g = 9.8 m.s-2. I understand that in order to calculate tension, I would need to multiply mass with acceleration. But i don't understand how i would in this case. This is the question for reference. Thanks for your help...
Hello! To this I did what was recommended and this is what it looks like
$$ F = mg $$
$$ F = \rho * V * g $$
$$ F = \ rho * \pi^2 * h * g $$
Than for the surface tension I did the same thing to get an expression for F.
$$ y = \frac {F} {2 \pi r}$$
Than tried to get F out and than...
At first I tried solving the problemteh following way:
Due to symmetry let the rods connected to the green rod have tension forces in magnitde T1 => mg = 2T1cos(a), where a is half the angle formed by the two rods. From tere I got an expression from the longer rods in the force projected by them...
Say I have a rod with a notch at the very centre and another ro with a notch at the very end. Both rods are identical in length radius materials etc. Who would be impacted by the notch more? And if then both were to support a load at the end of the rod (both in tension), what effects would the...
Tangential speed of 4 kg object is 8 m/s
At the top of the trajectory, there will be two downwards forces acting on 4 kg object, which are tension of string 2 (T2) and weight
##F=m.a##
##W + T_2=m.\frac{v^2}{r}##
Putting all the values, I get negative value for T2. Where is my mistake?
Thanks
I'm having trouble with this problem, I think I solved it but I don't know if what I did is right...
At first when the velocity is 0 and the spring is at its natural length, there's just gravitational potential energy, so $$E_i=mgh$$
And then, when the mass is released and then reaches its...
I know the solution for the problem of the tension on a rotating ring without gravity (tha is, ##\frac{mR\omega^2}{2\pi}##) - that I find simple enough. But I'm at a loss how can I change it to do with gravity :/
Any help is appreciated! (and apologies for the bad drawing)
Confused on how to find tension in rope (this would be the force acting on mass 2 that is causing work). Fnet wouldn't be 0 since the speed isn't constant and no acceleration is given. I'm sure I'm suppose to use the masses in an equation somehow, but I'm not sure how.
It makes sense that the...
My first question is actually, what happens when any two objects get near each other? This question is often phrased as "Why can't you really touch anything?" or "Why can't you walk through walls?" I have heard two answers: 1. the repulsion between electrons 2. the Pauli exclusion principle...
If you take a rubber band and fix it in a stretched position for an extended period of time, would it eventually lose its elasticity? If yes, then how can you calculate how long it would take until its elasticity decreases by a certain amount, say, fifty percent? If no, why not? How does the...
1. When an object attached to a fixed point with a string, is given a velocity and the string goes taut.
So it says in this book (Applied Mathematics 1 by L. Bostock and S. Chandler) that when the string goes taut, the component of the velocity of the particle becomes zero in the direction...
First and foremost, I've studied voltmeters and ammeters on my own, and online there aren't many resources to do so... forgive me in advance for eventual silly questions/doubts :)
I managed to calculate(intuitively) a tension of ##30.0V## per resistor, with basic procedures.
However, I'm...
hello
i have a drip tube with water dripping and when i increase the flow rate or frequency of drips they get bigger/more massive.
i see the equation mass x gravity = 3.14(tube diameter)(surface tension)
my mass is changing but not gravity, 3.14 or tube diameter so surface tension must be...
My result for this problem is correct, but I would like to submit to you the method I used since it doesn't convince me.
The problem asks for the maximum tension on the cable from the transition to 0 to 90 degrees; I firstly concluded just by thinking, not using formulas or particularly formal...
Hi, I have a question about a hanging rope - how do you find it's mass? I've been searching a long time, stumbled across some advanced calculus involving catenary functions and equations, but couldn't quite figure it out.
I'm puzzling over Exercise 1.14 in Thorne & Blandford's Modern Classical Physics. We are given that an electric field ##\boldsymbol{E}## exerts a pressure ##
\epsilon_{0}\boldsymbol{E}^{2}/2## orthogonal to itself and a tension of the same magnitude along itself. (The magnetic field does the...
Attempt:
By drawing the Free Body diagrams and calculating the different tensions, I got the following results
##T_1=\frac{(M_1+M_2)}{2}g##
##T_2=\frac{\sqrt 3(M_1+M_2)}{2}g##
##T_3=M_2g##
But, I am not sure what the answer is as although ##T_2>T_1## but ##T_3## does not depend on ##M_1##...
Hi
I'm having trouble to understand the centripetal force in a rotating rod with a mass in its end.
When ##90°<\theta<270°##, the centripetal acceleration is produced by the tension, which counteracts the radial component of the weight.
But what happens when ##\theta<90°## or ##\theta>270°##...
My guess is that the deformation immediately before would be the sum of elastic and plastic deformation, and the deformation after would be just the plastic deformation, and it therefore would decrease. Is this correct?
The whole question is:
One end of a uniform rope of mass 𝑚1 and length 𝑙 is attached to a shaft that is rotating at constant angular velocity of magnitude 𝜔. The other end is attached to a point-like object of mass 𝑚2. Find 𝑇(𝑟), the tension in the rope as a function of 𝑟, the distance from the...
The normal reaction from the ground and from block m, the force of gravity are the forces I feel should act on the wedge but since the wedge is a perfectly rigid body and the pulley(which is massless) is attached to it so will tension also act on the wedge as well?
Given a force of tension with a string attached to the front of the box, do we take the force as acting with an angle to the centre of the mass of phi or theta? Explain please?
the point on the string at a distance r from the pivot is rotating in a circle of radius r and hence a centrifugal force of magnitude mw^2r can be said to act on it where m = (M/L)r .
hence the T = centrifugal force
T = (M/L)(wr)^2
but my book says otherwise.
also can the string with mass be...
I mention the details in the book (verbatim) in the form of a paragraph in green below. Later I ask my questions in blue font for better reading.
"Surface tension also explains why hot, soapy water is used for washing. To wash clothing thoroughly, water must be forced through the tiny spaces...
The first part is easy, we have 2T= Mg
T= 0.5 Mg
Now for the second part where I'm having trouble understanding Morin's solution:
I take the normal force on a small circle arc to be N, we know that the y component of the normal force must be balance with Mg for the whole disk, therefore
Ny =...
I was looking for on the internet for a while without a success.
If I know that the surface tension of pure oil is ##\gamma_o=A## and I know that the surface tension of pure water is ##\gamma_w=B##
so if I have a mixture of water and oil with surface tension ##\gamma_m=C## am I able to know...
I tried considering a little piece of the ring (shaded black below) subtending angle ##d\theta##, and attempted to find the electric field in the vicinity of that piece by a summation of contributions from the rest of the ring:
$$dE_x = \frac{dq}{4\pi \epsilon_0 d^2} \cos{\phi} =...
Hi, I am looking for some guidance on how to approach this calculation. I have an air cylinder operating a lever assembly that then applies pressure to a pulley of which a belt is wrapped around. I need the belt to have about 4500 lbs of tension. How do I work backwards to figure the required...
I came across this diagram, the ##\gamma##'s are supposedly forces per unit length of the respective interfaces:
It's not clear what these forces are acting on. ##\gamma_{SL}## and ##\gamma_{LG}## look like they could be acting on a small bit of water right at the end, but I have no idea what...
Not much to add since the question is fairly simple, but again I'm wondering if applying tension at the free end of a cantilever beam affects the deflection it would have if only itself weight is considered. Intuitively, tension should tend to straighten the beam, and if it does, how to...
I am unsure how to go about this. I tried following the suggestion blindly and end up with with some cumbersome terms that are not the answer. From what I understand the derivative at each point would equal to T?
Answer: I just can seem to get to this. I think I'm there but can't get it in...
Q.1. The length of a stretched string fixed at both ends has a length of l=10 cm, mass per unit length ρ= 0.01 gm/cm. If the tension ' T ' is produced by hanging a 11 kg weight at both ends of the string, then calculate,
a) The wavelength of the first two harmonics,
b) The speed of the wave...
I know that it will probably execute something similar to circular motion. I thought of conserving momentum but I think there is an external force being applied due to the impulse which will prevent me from doing so.
I know that once I find the tension it would become very easy to find the...
Hello,
Looking for help on the following:
A crane is used to lower a vertical cylindrical pillar into a reservoir. The pillar has a mass of 4 tonnes and is submerged to a depth of 2.5m. It has a diameter of 1.1m.
The specific gravity of fresh water is 1125kg/m^3, and 9.81m/s^2.
Use a free...
The diagonal component of the boom's weight is ##R=w\cos\frac{\pi}{6}=\frac{\sqrt 3}{2}w##, and, considering ##R## as a "reaction", we have ##R_x=R\cos\frac{\pi}{3}=\frac{\sqrt 3}{4}w## and ##R_y=R\sin\frac{\pi}{3}=\frac 34w##.
I will also have...
a) I think you can just use Fnet = m*a, so for
student 1: a = 40N/60kg → a = 0.667 m/s^2
student 2: a = 50N/70kg → a = 0.714 m/s^2
b) Fnet = F - T, rearrange to solve for tension, → T = F - ma
Student 1, T = 40N - (60kg*0.667m/s^2) → T = -0.02N
Student 2, T = 50N - (70kg*0.71m/s^2) → T...
why isn't Surface tension reliant on the composion of the atm?
For an instance; If you place a glass of water in a room with regular atmosphere or you place it in a room filled with other gasses. The coefficient of surface tension of the fluid will change? Maybe?
why isn't viscoty of a fluid...
With the above in mind, I have a cable of E=60GPa, cross sectional area 7e-4m^2. I want to understand the relationship between the tension applied resisting the deflection of the cable when a force is applied so that the cable will not deflect more than 0.7m in this case. Take the force as...
So, I was studying about general properties of matter and topics like surface tension. I came across the phenomenon of water rising along a glass plate like in the picture. I looked for some mathematical interpretation of this on the internet and in some books.
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I've begun by drawing out the diagram. Since they want the tension in the 5m rope, I've broken it down into two vectors. I want to use T = mg + ma, but I don't think that's right because I don't have acceleration. Is there another formula I can use instead? Thanks!
I seem to remember from my school days that Tension Force can only be linear.
Is this true?
In 1 (in the graphic) the tension will follow the line of the rope
In 2 there is an unbendable, unbreakable, steel cable formed into an arch.
a ] In 3 which direction will the Tension be?
b ] In 3 if...