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.
I have a wire used for cutting cheese that gets pushed horizontally into the wire repeatably. Naturally the wires break as the wear. Currently, we just tighten the wire until it seems good but I am unsure how much the pretension in the wire influences the rate the wire breaks. I was looking to...
Homework Statement
A 1.0 kg box on a horizontal frictionless surface is accelerated by attaching a 1.5 kg mass as shown in the diagram. What is the magnitude of acceleration of the box?(Remember, both boxes accelerate.)
Homework Equations
F = ma
The Attempt at a Solution
I drew a free body...
Homework Statement
A crane lifts a 1250 kg load directly upward with a constant speed through a vertical
distance of 8 m. How much work is done by the tension in the crane cable?
Homework Equations
Im thinking its the work equation but this is were i got stuck
W = m(as)The Attempt at a...
Homework Statement
if a vertical string hangs with mass M attached to its end and is twisted by angle (theta) then
what will be the tension in the string
2. relevant equations
T= mg
torque= torsional constant x angular displacement
3. attempt to solution
i am not able to start with...
I was looking at some tensile testing data of some round bars with grooves machined into them, and based on the geometry of the groove I could not figure out how it was possible to withstand the high loads that it was seeing. I was stumped, but by some blind luck I saw a property listed on...
[moderator's note: moved to homework forum so no template]
In picture 3, A has touched the ground, so it has stopped. But B has a velocity upward. So in this situation, the cable is not straight. What will be the tension of the cable and what will be the accelertion of B in picture 3 ...
[moderator's note: moved to homework forum so no template]
This is a frictionless ideal pulley.
Are T_1, T_2, T_3 equal? If so, why? Please explain in details?
Homework Statement
A uniform chain of length L and [constant] mass per unit length λ is suspended at one A end by an inextensible light string. The other end of the chain B is held at rest at level of end A of the chain. [See image.] Now if the end B of the chain is released under gravity...
Homework Statement
A rope of mass m forming a circle is placed over a smooth round cone with half angle θ. Find the tension in the rope .
Homework EquationsThe Attempt at a Solution
Since the half angle is θ , the normal force N acts at an angle θ with the horizontal . The weight acts...
Homework Statement
Imagine one of those amusement park rides where you have a large rotating disc with seats hung by chains around it. As the disc spins, the seats also spin whilst rising up as well. The question asks for all answers to be written given the constants L, the length of the chain...
Homework Statement
An Atwood machine consists of two masses, M and m, which are connected by an inelastic cord of negligible mass that passes over a pulley. If the pulley has radius R and moment of inertia I about its axle, determine the acceleration of the masses M and m.
Homework Equations...
Blocks 1 and 2 of masses ml and m2, respectively, are connected by a light string, as shown above. These blocks are further connected to a block of mass M by another light string that passes over a pulley of negligible mass and friction. Blocks l and 2 move with a constant velocity v down the...
Homework Statement
http://ocw.mit.edu/courses/mechanical-engineering/2-06-fluid-dynamics-spring-2013/assignments/MIT2_06S13_ps2.pdf
Problem 7[/B]Homework Equations
##F=2*V/(a^2)*\sigma*cos(180-\theta)##
The Attempt at a Solution
With the problem statement given, it seems like the component of...
Homework Statement
A chain of mass ##M## and length ##L## held vertically by fixing its upper end to a rigid support. The tension in the chain at a distance ##y## from the rigid support is
Homework Equations
##F=ma## (Newton's 2nd law)
The Attempt at a Solution
Since net acceleration...
Homework Statement
A 1200 kg steel beam is supported by two ropes. Rope one is 20 degrees off of the vertical, and rope two is 30 degrees off of the vertical. What is the tension on rope two? (Answer should look like '2300 N'.)
Homework Equations
F=ma
The weight of the mass is defined as the...
Homework Statement
A cart loaded with books has a total mass of 20kg and is pulled at a constant speed by a rope inclined at 30 degrees above the horizontal. The cart moves a distance of 10m on a horizontal surface. The coefficient of kinetic friction between the cart and the surface is 0.45...
Three blocks are connected as shown in the uploaded picture. The strings and friction-less pulleys have negligible masses, and the coefficient of kinetic friction between the 2.0 kg block and the table is 0.17. What is the acceleration of the 2.0 kg block?
Homework Equations
∑F = ma
The...
If I have a U-shape wire frame and it contains a straight sliding wire and I dip this in soap, a film forms between the sliding wire and the boundary of U shape frame. Why is the force due to surface tension F = 2Tl where l is length of sliding wire?
They say there are 2 layers in contact...
Homework Statement
See image attached
Homework EquationsThe Attempt at a Solution
bii) Tc=mc(a+g)
Need help on Ci what I did is
(9x9.81) -uR-6g=10a
Have no idea what to do though really
Problem: A 22.0-kg crate is pulled along a horizontal floor by the ideal arrangement
shown in figure below. The force F is 300 N. The coefficient of friction between the crate and
the floor is 0.270. What is the acceleration of the crate?
Homework Equations
F = ma
Friction =...
I suspect my question will be somewhat unique, please forgive me if it's entirely out of place. (Please also forgive my ignorance when it shows, my knowledge of physics is extremely limited.) You might wonder why I'm asking it here, rather than on a guitar forum. Let me simply say that the...
if one string can hold a block of 100kg, how much weight can two strings connecting the ceiling and one single point hold a block?? is it 200 kg? if yes, then what about one string connecting the ceiling and one single point of the block two times, three times or more? [im sorry if the grammar...
The string on the violin with the highest pitch is the note E, which has a frequency of 329.6 Hz and a wavelength of 1.032 m. If the string has a mass of 180.0 g and a length of 32.0 cm and is currently producing a wave of frequency 328.1 Hz, how much do you need to change the tension in the...
Homework Statement
A stuntman whose mass is 70 kg swings from the end of a 4.0-m-long rope along the arc of a vertical circle. Assuming he starts from rest when the rope is horizontal, find the tensions on the rope that are required to make him follow his circular path at a height of 1.5 m...
I measure the tension in a pulley system with two masses (one smaller, one larger) where I pull the small mass down and let it go so that the system accelerates in the direction of the larger mass. This is without friction.
Then, I try to consider friction. Does the tension in the string...
Homework Statement
A rope of mass ##m## forming a circle is placed over a smooth round cone with half angle ##\theta##. Find the tension in the rope.
Homework Equations
##\sum{F}=0##
The Attempt at a Solution
I know how to solve the problem, but I have another way that I think should work but...
Homework Statement
What is the tension in the strap which the boy uses to hold onto the pack?
Mass of Boy=45kg
Mass of Pack=25kg
θ=42°
Coefficient of kinetic friction between boy and incline=0.35
Coefficient of kinetic friction between pack and incline=0.48
Acceleration of boy=4m/s^2...
What's the difference between surface tension and capillary force?
Surface tension, a tensor, is the force per unit length. Again surface energy is the energy required to increase the surface area by one unit. Is the surface tension a capillary force?
Homework Statement
This figure shows a uniform disk, with mass M = 2.5 kg
and radius R = 20 cm, mounted on a fixed horizontal axle.
A block with mass m = 1.2 kg hangs from a massless cord
that is wrapped around the rim of the disk.
Sample problem 10-8 (has picture diagram and detailed...
Two strings are adjusted to vibrate at 260 Hz. One string is tightened then 3 beats per second is head when the string vibrate at the same time. What is the new frequency of the tightened string.
I am using Fbeat=F1-F2; so wouldn't the answer just be 263 Hz
1. Find the tension in each cord if the weight of the suspended object is w. (I am only asking about part a)
2. Net force on an object in equilibrium = 0
3. part a) I know this isn't the typical solution for this type of problem but I don't understand why it's not working.
I used the...
Homework Statement
A 3kg block is connected to a 5kg block by a rope. A second rope is attached to the 5kg block and is being pulled by someone with a force of 11N. What is the tension on the rope between the two blocks? No friction
Homework Equations
F=ma[/B]The Attempt at a Solution
So I...
Homework Statement
Three pictures of equal weight (20 N) are hung by wires in three different orientations. In which orientation are the wires least likely to break? Orientation A: 15 degree with horizontal,Orientation B: 45 degree angle with horizontal, Orientation C: 60 angle with horizontal...
Hello everyone!
I was doing a homework problem tonight, and a concept came up that I didn't quite understand. Don't worry, this is not a question asking for homework help -- I've already done the research and figured out how to solve for the solution. What I don't understand is why it's true...
Homework Statement
A string of length L, which is clamped at both ends and has a tension T , is pulled aside a distance h at its center and released. a) What is the energy of the subsequent oscillations? b) How often will the shape shown in the figure reappear? (Assume that the tension remains...
Homework Statement
Using the uploaded picture we have to have a force diagram. And we have to break angled forces into components and indicate which forces are equal with equality. All the masses are up to me (2, 3, 4, 5 kgs)
Homework Equations
Write an equation for the vertical forces
Write...
Homework Statement
Two identical, uniform beams weighing 260 N each are connected at one end by a friction-less hinge. A light horizontal crossbar attached at the midpoints of the beams maintains an angle of 53 degrees between the beams. The beams are suspended from the ceiling by vertical...
I need to figure out if my companies pulling equipment can handle a 795 drake conductor (about 1 lb/ft) double bundled (times 2). The pulling equipment has a safe working load of 4000 lbs.
We are pulling it across 16 spans with a average span of 674 feet. the towers are 115' tall. Max sag...
Homework Statement
Homework Equations
Static equilibrium: Net force & net torque = 0
The Attempt at a Solution
Am i doing this correctly for part a? [/B]
I am a BSc product design student. This is one of my assignments and I have never done physics in my life. Can anyone help? I do not understand at all!
1.
Calculate the force needed to move the wire in the figure (Figure 1) if it holds a soapy solution (surface tension is 0.025 N/m) and the wire is 16.0 cm long.
Express your answer to two significant figures and include the appropriate units.
2.
γ(surface tension) = F (force) / l (length)...
Homework Statement
You swing a ball around a piece of string(vertically). M = 0.150kg r= 1.10m
Calculate the Tention at the bottom of the arc assuming velocity is twice as fast.
Homework Equations
When I do the problem I'm not sure how to set up the NetForce = ma
How do which force is...
Homework Statement
A rope is connected between two fixed points that are separated horizontally from one another by 10 m. The point on the left at a height of 5 m [coordinates (0,5m)], and point on the right is at a height of 10 m [coordinates
(10m,10m)]. A 100 lbs weight hangs from the rope...
Homework Statement
In my workbook it gives an example and solution for the following question:
The following diagram is of an atwood machine, which is a machine consisting of two masses: a massless string and a frictionless pulley. Due to the unequal masses on either end of the string, the...
This problem was given verbally during a class period, so I will set it up in my own words.
A bullet (.012kg) is fired at a block (.800kg) hanging on a strong, massless string of length 1.6m. After the collision the bullet is embedded in the block. When the block is .8m above its original...