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.
Hello,
I need to transmit motion between a servo motor and a pulley through a cable. In order to do that, I've screwed a pulley to the servo and fix the cable on both the motor pulley and the pulley. I am working in a scale where the radius of the cable cannot be neglected due to a precision...
Okay so I am having trouble understanding the relationship between Tension, Net Force, and Acceleration. For example, if two objects in a system are connected by a tension force and accelerating at the same speed, but with different forces acting on each object, would:
1. The net force be equal...
Hi guys, I feel that this question has a very straightforward answer but I am just not quite grasping it. The first picture is the homework question, the second is the free body diagram I drew.
I know that a = F/m and I know the solution should be:
a = (P - m1*gsinθ - m2*gsinθ) / m1 + m2...
(The weight scale = 10 kg).
After initial force, now the mass is lowering down at constant speed of 1 m/s.
The motor with pulley's radius of 1 meter is exerted 100 Newton m to keep constant V.
The motor speed is about 9.55 rpm.
* All other weights, inertia and frictions of the system is...
I used the above equations to solve for tension, torque, inertia, and angular acceleration.
Are the formulas I used correct for the given system?
How can I calculate Inertia from the trendline equation, I'm drawing a blank.
I know I have to find the x and y components of T1 using 400cos(55) and 400sin(55) and I know that the x-component of T1 will = the x-component of T2 but opposite sign to give 0. But idk how to get there and what do to for the y-component. I think I found the weight, I think it’s 32.42g but I’m...
The system is in rotational equilibrium and therefore experiences no net torque, meaning all individual torques must add to zero.
τNET = 0 = FFTsin(θ)L - FgL - Fg(L/2)
τNET = 0 = FTsin30°(0.6?) - (0.5)(9.8)(0.6) - (2.0)(0.6/2)
My only problem (I think) is figuring out what the length L is for...
Homework Statement
Once under way at a steady speed, the 1100-kg elevator A rises at the rate of 1 story (2.74 m) per second. Determine the power input Pin into the motor unit M if the combined mechanical and electrical efficiency of the system is e = 0.76.
Here is a link to the diagram for...
Homework Statement
A tiny, 0.60g ball carries a charge of magnitude 8.0 mircoC. It is suspended by a vertical thread in a downard 300 N/C electric field. What is the tension in the thread if the charge on the ball is (a) positive, (b) negative?
Homework Equations
E=F/q or E=mg/q
When i use...
Homework Statement
Two objects are connected by a string that passes over a frictionless pulley, where m1<m2 and a1 and a2 are the magnitudes of the respective accelerations. Which mathematical statement is true regarding the magnitude of the acceleration a2 of the mass m2?
(a) a2<g
(b) a2>g...
Homework Statement
Homework Equations
Fg=mg
The Attempt at a Solution
I tried to set this up as two "triangles".
&&
left triangle:
sin(37)=mg/T
T1=mg/sin(37)
T1=202.72
right triangle:
sin(53)=mg/T
T2=mg/sin(53)
T2=152.761
I now know the correct answers are T1=73.4N and T2=97.4...
Homework Statement
A sledge loaded with bricks has a total mass of 18.0 kg and is pulled at constant speed by a rope inclined at 20.0° above the horizontal. The sledge moves a distance of 20.0 m on a horizontal surface. The coefficient of kinetic friction between the sledge and surface is...
Homework Statement
Given the picture:
Make the free body diagrams of each body and the pulley. Remember that there are two different strings therefore there are two different tensions.Assuming that the mobile of mass M starts from rest and has a displacement D at a time t, and the bodywith...
Homework Statement
In figure 12-34, a uniform beam of weight 500N and length 3m is suspended horizontally, on the left it is hinged to the wall and on the right end of the beam is a cable attached to support it. the cable is attached distance D up the wall from the hinge. The least amount of...
IMPORTANT!
TEXT IN GREEN HAS BEEN ADDED AND IS CORRECT
TEXT IN RED HAS BEEN REMOVED AND IS INCORRECT
1. Homework Statement
Question: An energetic father stands at the summit of a conical hill as he spins his 25 kg child around on a 5.7 kg cart with a 2.3-m-long rope.
The sides of the hill are...
Homework Statement
A man, with a mass of 85kg, swings from a vine with a length of 11m. If this speed at the bottom of the swing is 8m/s, what is the tension if g = 10m/s^2?
Given:
m (mass) = 85kg
r (radius) = 11m
V (speed) = 8m/s
g = 10m/s^2
T = ?
Homework Equations
Fc (centripetal force) = T...
Dear Everyone,
I am having trouble with how to start with one part of the question:
"In this exercise, we derived the PDE that models the vibrations of a hanging chain of length $L$. For convenience, the x-axis placed vertically with the positive direction pointing upward, and the fixed end...
I isolated the member ABC and drew the free body diagram:
α is then calculated using inverse tan: Tan-1=(6.25+15)/50=23.03
Then force of member BD on the joint can be found by sum of all moments around point A.
Then Ax is calculated which is equal to BD×Cos(α)=235.2×Cos(23.03) Ax=216.48...
Homework Statement
A 35 kg mass is being raised by a cable with decreasing speed. At the instant the upward velocity has a magnitude of 1.6 m/s and the downward acceleration has magnitude of 1.2 m/s2, what is the tension of the cable?
m=35 kg
v=1.6 m/s
a= -1.2 m/s2
g= 9.81 m/s2
Homework...
Homework Statement
Calculate Tension (Tp) and (TQ) (P is the mid point)
Homework Equations
T - mg = maThe Attempt at a Solution
For Q (massless rope)
Tq - 1.9g - 0.2g - 2.9g = 5a
Tq = 5(g+a)
Tq = 5 * 10 = 50N
Given answer = 50N
(Calculation of Tension for Q is clear to me, but I am...
Homework Statement
A simple pendulum, suspended from a fixed point cosnits of a light cord of length 500mm and a bob of wieght 2N . The bob is made up to move in a hotizontal path. If the max tension is 4N show whether or not it is possible for the radius of the path of the bob to be 300mm...
Hi guys,
Bringing myself back up to speed with bolt tightening, would really appreciate if anyone has some resources or answers to these questions:
1. The proof load for torque tightening, and proof load for tension tightening
2. Main advantages and disadvantages between the two
3. What is...
I am a high school student and currently studying Mechanical properties of fluid.
We are taught surface tension in a very introductory level and most of it is about liquid-gas surface tension.
We are taught that liquid-vapour tension is the atrractive forces that water molecules experience at...
Hi! Here's a tricky thermodynamics problem, I hope you can help with it.
1. Homework Statement
The boundary between two different materials can be divided into two different kind of phases: bulk phases and surface phases. For example, let's consider a boundary between water and air. We can...
Homework Statement
A block on an inclined surface is connected to another block that is hanging over the top edge of the incline, (as shown in the attached diagram). The system is moving in such a way that block B (mass = 3.0kg) is moving downwards, as block A slides up the ramp. The...
Homework Statement
Hello everyone, I am doing an experiment and I've hit a snag with my calculations. I am looking at how concentrations of soap affect surface tension in water. I am have been using the capillary equation and capillary tubes for my calculations. I have practiced this method for...
Homework Statement
Find the tension in each section of string in terms of ##θ_1##,m and g.
Homework Equations
Equilibrium of force,dimensional analysis of force.
The Attempt at a Solution
The support points are at rest and in each points,there are two equal tension force acting in opposite...
I was reading Fundamentals of Inket Printing and it said the following:
"The surface tension in a liquid causes a force to act in the plane of the free surface
perpendicularly to a free edge in that surface."
Can someone explain to me what this means? What's the direction of the force? I have...
Hello Forum,
I have been reading that tension, which is identified as a force in introductory physics books, is not really a force. For example, at a certain point ##P## along a rope under tension, the tension can point both left and right.
I understand that there are the stress and strain...
A 30 kg sphere is held stationary by two cables. One cable is attached at 60° above horizontal. The second cable is horizontal and attached at the side of the sphere. Find the tension in both cables.
Newton's 2nd law: F=ma, which means a = (∑F/m)
We can also find the weight: W = mg
Let's say...
Homework Statement
A mass M1 is sliding across a table with coefficient of kinetic friction μk. A string is tied to this mass and runs over a pulley, drops vertically and is tied to another mass M2 which is falling. The pulley is connected to the table by a support. The pulley is a solid...
Homework Statement
A 12m long board weighing 4kg is suspended by ropes on each end. 3m from the left side a painter is standing, closer to the first rope.
Find the tension in both ropes.
If the painter were to get off of the board, and the second rope snapped immediately after, find the...
Homework Statement
A mass of 50 grams hangs in equilibrium on a string. The mass is pulled aside and upwards by a force of 0.3N which makes an angle of 30° with the horizontal. Find the angle that the string makes with the vertical and the tension in the string.
Homework Equations
Body is in...
In a web tension control system, where feed forward is to be used. A tension set point is desired let's say 20lbs, and a load cell system provides feed back. There will be dead weight on the load cell as the material with no pull sits on top of the load cell system. [Obviously I will need to...
Homework Statement
Homework Equations
∑MA = 0, where A is the pin.
Tx = Tcos150
Ty = Tsin150
The Attempt at a Solution
I've drawn in the 100kN force of the beam's weight, and identified that ∑MA = 0. I attempted to find the moment arm, but really wasn't sure how do to it, or if it would even...
Homework Statement
Spin 340 gram mass at the end of a 72 cm string in a horizontal circle around head 2.5 rev/s. Calculate tension
Homework EquationsThe Attempt at a Solution
I know tension might be equal to mass times centripetal acceleration, but I’m not sure
Homework Statement :
[/B]
Homework Equations : F = ma[/B]The Attempt at a Solution :
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The sum of the vertical forces for the second block is (mg) - T (tension). The tension of the second block is the parallel component of the first block which is (mgsin40). Therefore, the sum of the...
Imagine a tall block of wood sitting on the ground. Then imagine a rope resting on the block with both ends dangling off both sides of the block. Then someone attaches a ball to both ends of the rope. Assume the balls are equal in mass, thus the system is in equilibrium. Now the middle of...
Homework Statement
A UTA Trax train engine can apply 96050 Newtons and locomotive has a mass of 1750 kg. The passenger car has a mass of 949 kg.
(A) If the train accelerates at a rate of 1.29 m/s/s, how much friction is present in the passenger car? (Assume the locomotive moves...
I'm a little confused with the application of laws of motion on a man climbing a rope. Suppose a man of mass Mg is climbing a rope with an acceleration a. Rope is massless. Now if look through the frame of the piece of rope held by the man, there is a force Mg downward by man, ma downward...
Homework Statement
Homework Equations
Σtorque = 0
Σfx=0
Σfy=0
torque= F r sinθ (θ is the angle between the r and the F)The Attempt at a Solution
OKay, now i know how to solve this, but it's like i asked myself, how to know if this is a question that i am supposed to use
Σfx=0 and Σfy=0...
Homework Statement
https://imgur.com/KANlHh9
The problem and my equation for finding the tension in rope one are shown in the image above. I am stuck on finding the tension for the horizontal component of the second rope's tension and finding the angle theta
Homework Equations
F=ma
F=T-WThe...
Homework Statement
The coefficient of kinetic friction between the block of mass m1 = 2.5 kg and the plane in Fig. 6 below is 1/6. Find (a) the acceleration of the block and (b) the tension in the string. Take g = 10 m/s2.
Homework Equations
Fnet=ma
The Attempt at a Solution
please i don't...
Homework Statement
A system, consisting of a wide rope of mass 0.10 kg between two blocks each of mass 0.10 kg, is lifted by an applied force F = 9.0 N (Fig. 4 below). (a) Find the acceleration of the system. Find the tension at (b) the top of the rope, and (c) the bottom of one-fifth of the...
Homework Statement
A charged cork ball is suspended on a light string in the presence of a uniform electric field.
E=(3×10^5 N/C)i+(5×10^5 N/C)j. The ball is in equilibrium in the field.
Find the charge on the ball. The acceleration due to gravity is 9.8 m/s2 . The mass of the ball is 0.7g. The...
Homework Statement
The figure below shows the speed of a person's body as he does a chin-up. Assume the motion is vertical and the mass of the person's body is 72.7 kg. Determine the force exerted by the chin-up bar on his body at the following times.
My answers:
Homework Equations
F = ma...
In the last years a discrepancy between two methods to measure the Hubble constant appeared. Measurements based on redshift and the cosmic distance ladder produced results of about 73 km/(s*Mpc) while measurements based on the cosmic microwave background lead to results of about 68 km/(s*Mpc)...
[moderator: text edited to change the phrasing.]
There is a question that that says: a 50 kg weight is suspended from the bottom part from a rope.
If the rope has a weight of 100N. Then what is the tension at each end of the rope( the top part connected to the ceiling and the bottom part to...