Work Definition and 998 Threads

Hi, Could I please ask where I am going wrong with this very simple question: Here's my answer (units implied): A force of 20 extends the spring by 1/100 and so the Work Done in performing this extension is 20 * 1/100 = 1/ 5 Now, the work done in extending a spring is given by the formula...

if you fed a rectangular waves to a radio antenna, would it still produce radio waves? does it have to be a sine wave?

This is purely for fun, as it won't affect my plot direction whatsoever. Which of my scifi created humanoid races would you prefer to work with and why? Which would you not want to and why? Based on their behavior only? Race 1: Take a positive view most all the time of situations, but can...

Hello I am new here lived in New York with my 2 kids and looking for a teaching job. I applied online but can't get response from them. I have received an email yesterday stated that they are going to give me an opportunity an engineering firm. They want me to fill a form with my all details...

The problem is based on a projectile-spring launcher. A ball is loaded into a tube that pushes back a spring and is then launched. The ball was launched straight horizontally not at an angle. I'm trying to find the work done on the ball by the spring. The info I have: Displacement of spring =...

Hello, I'm confusing about the basic terms about Conservation of Energy, Potential Energy and Work. Consider that we have a mass ##M## above the ground (zero point) distance of ##y_{0}=h##. When we release the mass it will accelerate through it's way to ground. So the work is made by a field...

A box is moving at a constant velocity. 250N of applied force is acting on a box while 250N of friction is acting on it on the opposite direction. If the box travels 4 meters in the same direction as the applied force, how much work is done? I know that work = force * displacement. Is the...

I understand that work is done when (a) a force displaces an object, (b) energy is converted from one form to another, (c) heat is transferred between a system and its surroundings, yet I have trouble giving a precise definition for it. Everywhere I go, the definition of energy is "the ability...

if I shoot the football, the ball will recive a force in specific direction, and it would follow that direction. Does the work is done by me when I shooted the ball, or the ball does work when it moves all the period after my shooting ? the work includes force and displacement , so who does the...

Buffer is a solution of weak acid and its conjugate base which resists the change in pH when strong acid/base is added to the solution. But how does it work? Consider, HA + H2O ⇄ H3O+ + A- When we add strong acid, the H+ from the strong acid reacts with the conjugate base A- to for HA...

My teacher told me that answers are F=1200 N for lifting straight up and F= 360 N for using the ramp. I can get the force for lifting straight up by using 1800=F(1.5)cos(0) but I do not understand why for using the ramp the equation 1800 = F(1.5)cos(72.5) does not produce the correct answer.

So I've been digging this problem for quite some time, and still can't figure out a way to obtain work done in AB. I do understand that work done in AB = area under the graph. However, I can't figure out how to obtain the volume at B. I can't use PV=nRT since I am unable to obtain the...

I see physics problems asking one to calculate the work done in climbing stairs. However, isn't the system the person, and isn't the person not having any external work done? Then how can we say they did work? Now I know when climbing or raising an object, work=mgh=potential energy. But if the...

Attached is an example from my Tipler physics book of a determining the power delivered from a cars engine. I get the derivation(math), but am having some issues with the understanding/concept. Mainly, isn't Power=Work done/time. If so, they define the system as Car-earth. There is no external...

Given: V_1 = 10 L, V_2 = 22 L Not sure what I need to do here. We are told to ignore heat transfer, and the problem suggests that this is not a steady-state problem. The gage pressure is given, so I think that means we need to calculate for the absolute pressure, which would be 997 kPa. Cp and...

Hi All, I understand carbon sequestration in the simplest sense is capturing and storing carbon. As seen in the title, I'm going to split this into two sections. i) How does it work? I imagine that trees, in a sense are doing this. They take in the carbon from our atmosphere and is stored...

Fa = Force applied on the cart by the parent Fax = x component For the force applied on the cart by the parent Fay = y component For the force applied on the cart by the parent Ff = force of friction The method I thought to use was to solve for Facos, Fasin and then use pythagorean's theorem to...

I downloaded the amsmath package and am using the command \usepackage{amsmath} and its not working. I have used it a few years ago, but can't remember whether I had this problem and what the solution was- I think it's something as simple as saving it in the right place if I recall quickly -...

NOTE: THIS IS THE GRAPH PROVIDED At first I approached this problem attempting to solve for the total work done, using the formula Wtotal = Wmaxforce - Wfriction I then subbed into the formula, representing the values of work as their torque value times theta, which gave me a longer algebraic...

The formulas we have been given include Potential energy=mgh, Stored strain energy=(1/2)K(change in X)^2, , Kinetic energy=(1/2)mV^2, Work=F(change in d), Force=K(change in X). Not sure how exactly to answer the question.

Let R_{1} be the reaction force on the jumper from the ground. Assuming this is larger than the combined mass of the 3 sections of human, if we consider the entire system we will get an upward acceleration (a is labelled as the acceleration of the COM; it will of course vary from the bottom to...

From reference: https://www.elprocus.com/phase-locked-loop-operating-principle-and-applications/ It says that the PD produces an output that is DC level proportional to (Fi - Fo) (I think it has typo. It should be '-' but they've printed '+'). Then the low pass filter removes the high...

In my study of electrical engineering I have been told that the voltage across a resistance is V = IR. If I connect a resistor R and a power supply of 5V 2 A then how does ohms law work here? I could change R to anything I want but the source would stay at 5 V and 2 amps regardless of what I do...

Consider a spring with one end attached to a wall and the other to a free mass, which is then stretched so some potential energy U. After it has been released and has de-stretched, the change of elastic potential energy is -U which equates to the negative of the work done by the spring force on...

I read on the Internet that the work done by a (rigid) body = the change in Kinetic energy. What if I lift a rigid body slowly and vertically by 1 meter above the Earth's surface so that the initial velocity = final velocity =0? According to the Work Energy theorem as stated on many sites on...

Summary: I am not a physics student but I really need to prove that aluminium will not deform 10m underwater Hi I am doing a project of a product which will sink underwater. It will be a sealed cylindrical vessel, length 2m, width 1m, thickness 0.02m. Aluminium 6061t will be used with a yield...

At the early 20th century, people can only achieve fusion by smashing atoms together via particle accelerators. That obviously outputs much less energy than input, and takes forever just to fuse a single gram of hydrogen to helium. Currently, speaking of thermonuclear reactors we always think of...

[Mentors’ note: Elaborate explanation of unworkable perpetual motion machine removed]

Homework Statement: A perfect hemisphere of frictionless ice has radius R=7 meters. Sitting on the top of the ice, motionless, is a box of mass m=7 kg. The box starts to slide to the right, down the sloping surface of the ice. After it has moved by an angle 11 degrees from the top, how much...

Homework Statement: Hetsut is the foreman of a construction project in ancient Egypt. He needs to move a giant block of stone, of mass 12 metric tons, from the docks to the temple grounds. He can go along the roads by traveling 295 meters east, then 89 meters north. Along the roads, the...

Homework Statement: A perfect hemisphere of frictionless ice has radius R=6.5 meters. Sitting on the top of the ice, motionless, is a box of mass m=6 kg. The box starts to slide to the right, down the sloping surface of the ice. After it has moved by an angle 20 degrees from the top, how much...

Homework Statement: Mike the Mailman takes his oath seriously: "Neither snow, nor rain, nor heat, nor gloom of night stays these courageous couriers from the swift completion of their appointed rounds". Even though a blizzard is raging outside, he goes out to deliver the mail. He makes four...

E final = (1/2)(500)(1.14012)^2 = 324.968 J E initial = (1/2)(500)(0.5)^2 = 62.5 J E final - E initial = 262.468 J

Hi all. I'm currently an aerospace engineering undergraduate student in my second year, but I'm going through a very confusing process of second guessings and would greatly appreciate advice from older people who work in the Aerospace or in the Physics/Astronomy fields to help me compare the...

I am making a robot and was wondering if this mechanism will work to turn my robot. Below is a small diagram of my robot. The main wheels are by the circle and there are a few small not power ones for stablisation in the tail. If I rotated the part pointed to in the tail or just the tail would...

https://www.physicsforums.com/attachments/250022 For the part (a), set the tension of the string that pulls the elevator be ##T_1## and the tension that pushes the counterweight be ##T_2##. Then we have the following equations: $$T_1−1200g=1200 \cdot 1.5$$ $$1000g−T_2=1000 \cdot (−1.5)$$ where...

I considered the work done by the frictional force in an infinitesimal angular displacement: $$dW = Frd\theta = (kr\omega) rd\theta = kr^{2} \frac{d\theta}{dt} d\theta$$I now tried to integrate this quantity from pi/2 to 0, however couldn't figure out how to do this$$W =...

This is the figure for the problem: 1.) Solved for initial total EPE of the system EPE system = (kq2q3/a) + (kq2q1/b) + (kq1q3/√a^2 + b^2) 2.) Solved for final EPE of the system negating q1 as if it were off to infinity EPE system final = (kq2q3/a) 3.) Plugged values into equation W =...

Applying the dot product to the position vector and force vectors yields the result that the force vector is always at 90 degrees to the position vector, namely that it is directed tangentially. The mark scheme gives the work done as 0, however I don't agree. I believe they got this by finding...

I'm having no luck at all generating LaTex. I'm using the Safari web browser on an iPad. Example: \frac a b I can see the LaTex formatting on other posts though. Note to observers; I'm practicing LaTeX in this older message. We start...

I happened to come across an old thread, "What counts as crackpottery?" and the above question came to my mind. The story is well known that he developed his results on his own without access to standard mathematical notation, and so when he began corresponding with mathematicians at...

I am interested to understand the current theoretical status of Landauer's Principle and related ideas. I am looking for key papers and results in the subject. I will highlight one key paper. An improved Landauer principle with finite-size corrections Abstract: Landauerʼs principle relates...

Summary: How does a cell of SRAM work? I have computer science minor, and we have been given the task of finding out the differences between SRAM and DRAM. Simple enough? I thought so, until I got into the circuitry of a SRAM cell and got interested in finding how it works for storing, reading...

has anybody used a tip47g transistor? i can't get it to act as switch for a larger current. i have tried reading the datasheet. the datasheet won't work.

I know that by physics definition if displacement is zero, work is zero. However, if I push an object 5 m to the east, and then move to the other side of the object and push it 5 m back to the west. I think in this case I have always done positive work on the object and hence the total work...

So I can across this question in class and there were a multitude of answers, such as 0 work (J), my answer was 8100J based on the fact it doesn't tell you any distance moved, just that its 45N for 3 minutes, so my logic was 45N per second so 45*3(60)=8100J

I have a Hamiltonian ##H_{\lambda(t)}##, where ##\lambda (t)## characterizes a time dependent path in parameter space. The parameter is changed in finite time from ##\lambda (t_i)## to ##\lambda(t_f)## . At ##t = t_i## the system is in the intial state ##|\Psi>##. What is the work done on the...

I am reading Landau's Vol 5 on Statistical Physics and have trouble grasping some concepts in Section 20. If I understand this correctly, the body and the medium are in direct contact and can exchange work and heat while the object can only exchange work with the body. So the minimum...

Hello May I ask: "What is the guiding philosophy of the Principle of Virtual Work?" I do understand it an how to use it, in classical mechanics. (And I will openly admit that I do not entirely understand what I am looking for, or what I am asking.) But what is happening at this moment in...

Work is basically energy applied thru a force to move an object right? Or another way put it is just force thru a displacement, which can be thought of as "energy used" I see definitions saying it is a transfer of energy, not sure why they mean by that