Work Definition and 999 Threads

Work - Energy principle states that work of resultant force or sum of work of all forces acting on some system equals change in kinetic energy of the system. For inviscid fluid flowing in a pipe such theorem can be used to derive Bernoulli's equation because as fluid flows it is subjected to...

I really can't get my head around the concept of pulsed plasma thruster. All I know now is that it utilizes ##\vec F=q \dot {\vec r}\times \vec B##. Could someone explain the mechanism to me, please? Thanks!

1) What is the relationship between gravitons and the curvature of space-time? 2) As gravitons move at speed c, the curvature of space-time is not instantaneous either, so how the curvature sets in or disappears gradually (for theoretical example if mass disappears suddenly upon collision of...

Got a question from my science exam that I'm not sure how to figure it out. All the context I was given is attached. My attempt: Mass=26kg 26a = Force Work = 26a x 2 Work = 52aNot sure how to figure it out, as 52a is the wrong answer.

I first worked out the buoyant force using rho = 1000, g = 9.8 and V = 1. (this gives Fb = 9800) I then worked out Fg of the tank (5 x 9.8 = 49) Then I used Fnet = Fb - Fg - T = 0 to work out tension as 9751. I thought the work done would be the work done by tension (9751 x 50.4), but I'm not...

Let’s say we have two persons who are going to travel from Central Park in New York to the Golden Gate Bridge in San Francisco. One is going to walk and the other is going to use his skate board. And let’s say they weigh the same and take the exact same route. the question is this...is the...

Do virus masks have any effect on preventing or reducing risk of infection from CV19? Have there been any studies on this?

I am still trying to find somewhere to post to report this problem. If try to visit and post in Feedback, or if I try just to VISIT the "Advertisements" topic there, the only page that loads is this: "Page could not be loaded,... " and I cannot even post the whole page message here because...

Summary:: Basically the title: It seems that one of the formulas I use considers the pressure in PdV to be internal, when as far as I know, it is external. So to my understanding, in w = PdV, the pressure is the external pressure. However, I get tripped up because in my textbook, for a...

What does a MechE/EE/ChemE usually do in this industry? I think that CS/CE works in the software department and architecture. For circuit and stuff, EEs will be working on that. ChemE works on the actual manufacturing of chips. Materials E work in this department too, I think. Am I correct...

Found a question on another website, I have the exact same question. Please help me Goldstein says : I do not understand how (2.34) shows that the virtual work done by forces of constraint is zero. How does the fact that "the same Hamilton's principle holds for both holonomic and...

So... I've been writing my work about the vacuum and quantum vacuum. Now my problem is that I've come to realize that I can't really bring my thoughts and research onto paper the way I would like it. I am now in 12th grade in high school I know that this is a crazy demand but hear me out: I...

So the formula for power is Power = work / time. There's two types of energy transfers: heat and work. How do you calculate the power of something using heat energy in BTU/hr when BTU isn't work?

a) ##T_A=\frac{p_AV_A}{nR}=300.7K, P_A V_A=kL^2=nRT_A##, ##P_B S=k\frac{L}{2}\Rightarrow P_B V_B=k(\frac{L}{2})^2 \Rightarrow P_B=\frac{kL^2}{2V_A}=\frac{P_AV_A}{2V_A}=\frac{P_A}{2}##, ##W_{spring\to gas}=\int_{L}^{L/2}kxdx=-\frac{3}{8}kL^2=-\frac{3}{8}nRT_A####\Rightarrow Q=L+\Delta...

How does a 3 stage linear actuator mechanical work. I can only find a regular linear actuator mechanical but I'm unsure how will the last stage go up and down. Anyone got a poor 3d drawing for a better understanding.?

How would you go about calculating the work done in morphing a square current-carrying loop into a circular current-carrying loop, without change in length while maintaining the same angular orientation with an external magnetic field. My book suggests defining P(potential energy) = M.B (dot...

The question is given in 3 parts. For first part, process is isochoric so Work done=0. We know here that at end of the process (a), T2=T1 while V remains constant (we can take it as V1) so P2=2P1. For second part, process is isothermal so T is constant. At end of process we reach P1 again from...

I used the Change in Kinetic Energy and equated that with the Work Done. The "Work Done" part comprises of two different functions- one is work done by Gravitational Force while the other is the work done by frictional force (or the brakes). /Delta KE (magnitude wise)= 0.5*1350* (20^2)=270,000...

Two things that I think I should say before I describe what I did: First, I do not have any physics-related background (but I have a degree in CS, and I'd like to think I have a good enough grasp on math to be able to understand equations describing motion of objects). So please forgive me if...

In private discussions, another member @burian and I have been discussing why, in compression and expansion of a gas, the work can be calculated from ##W=\int{P_{ext}dV}##. We thought it would be of value to open the discussion to the full membership. Burian last asked about: When the...

How does putting it potentially inbetween 2 basis states, which U will measure only later, on, do it!? That seems like magic, to me. And yet I accept that it does. Somehow.

The question is to find the resistance between AF (top 2 points). Let the far right unlabelled vertex of the pentagon be B. Why can we say that points O and C are at the same potential? I get that both points O and C appear to be at 'half the path' if you consider AOF and ABCDF, and so potential...

Particle X of mass 2 kg , and particle Y of mass m kg are attached to the ends of a light inextensible string of length 4.8m. The string passes over a fixed smooth pulley and hangs vertically either side of the pulley. Particle X is held at ground level, 3m below the pulley. Particle X is...

A car of mass 1200 kg accelerates up a hill inclined at 10 degree to the horizontal. The car has initial speed of 10 m/ s and final speed of 12 m/s after 60 s. Air resistance and friction may be ignored. Find the average power generated by the engine. The and in the textbook is 36000 W, iam...

Suppose I am sliding a block very slowly on a rough surface. If the block has traveled ##d## distance then work done by me is ##W_1=\mu mg d## and that by friction is ##W_2=-\mu mg d##. Now the energy transferred from me to block is ##\mu mgd## and that taken by friction from block is ##\mu mgd...

A golf ball of mass 45.9g is hit from a tee with speed 180km/ h. The ball rises to a height of 20m having traveled along a curved path of length 61.875m. At the highest point of its path the ball is traveling at 144 km/h a) Find the magnitude of the avg resistance force acting on the golf ball...

To calculate the sum of numbers between to set integers, at any separation, without adding individually. End set number times ( ½ End set number divided by Separation increment) plus ½ End Set number E ( ½E / S ) + ½E = SUM For example: • To calculate all whole numbers 1 – 100 (i.e...

A golf ball of mass 45.9g is hit from a tee with speed 50 m/ s. The ball lands in a pond 5m lower than the tee. When the ball lands in the pond it has traveled a curved path of length 160m. The resistance acting on the ball has magnitude 0.3N a) Find the speed of the ball just before it hits the...

A sky diver of mass 80 kg falls 1000m from rest and then opens his parachute for the remaining 2000m of his fall. Air resistance is negligible until the parachute opens. The sky diver is traveling at 5 m/ s just before he hits the ground. Find the average resistance force when the sky diver is...

A football is kicked from the ground level with speed 15m/s and rises to a height of 1.45m. Assume that air resistance is negligible a) Find the speed of the ball when it is 1m above the ground Increase in GPE= loss of KE mgh=1/2mu^2-1/2mv2 10×(1.45-1)= 1/2×15^2-v^2/2 V= 14.7 m/ s But textbook...

A box slides down a smooth ramp. The height of the ramp is 20cm and the length of the ramp is 2.5m. The box starts from rest. What is the speed of the box when it reaches the bottom of the ramp? I don't understand how to solve this. Pls help

Why are lights reflecting off horizontal surfaces like the road, water, or snow horizontally polarized? How does the process happen?

A child of mass 40kg slides down a playground slide. The child starts from rest at the top of the slide, 2m above the ground. At the bottom of the slide it's slope levels off. a) Find the child's loss of GPE I got the ans 800J there is a constant resistance of 112N throughout b) find the...

A girl of mass 50 kg travels down a water slide. She starts at the top with a speed of 2 m/s and descends through a vertical height of 5m. a) Assuming that there is no resistance, find her speed when she reaches the bottom of the slide I got the ans 10.2m/ s b) the girl's actual final speed is...

A box of mass 25kg is pulled 5m across a smooth floor by rope with tension 22N. The rope is inclined at 40 degree to above the horizontal. There is a frictional force with average value 12N. The box starts from rest. Find the final speed. Iam getting the ans 1.97m/s. The textbook ans is 1.39 m/s...

This is the solution from my textbook, and I have some questions about the method The mass of hanging chain : $$m_h =\frac m 5$$ the center of mass of the hanging chain : $$h_1 = - \frac{1} {2} \cdot \frac L 5 = - \frac L {10}$$ (the minus sign here means that it is under the table surface)...

Does anyone have experience with such strange behavior in Monte-Carlo methods? I think it is a conceptional problem and I am just missing a key point in how to set up the integration instead of a error in my code itself. I use data files from LHAPDF and also checked that my variables give the...

Hi, A Korean friend owns me money and plans to pay partial with his airconditioner. But the aircon model came from Korea. I just want to know if an air conditioner like Carrier of a specific model made in different countries have the same design, or do they have separate say Korean design, or...

I am struggling to understand shocks in a one dimensional lattice with a linear spring connecting the masses. Say I have a one dimensional lattice with a linear spring constant, k and lattice spacing a. If the particles in the lattice has mass, m then my speed of sound c is a*sqrt(k/m). That is...

Hello everyone, I was curious about how do we define a physical quantity and mathematical relation between them. For example: Work done is defined as product of force along the displacement and displacement i.e W=Fcos(theta)d. Now this definition is given in books straightforward but my...

Is there any existing work focusing on analyzing finite element visualized results and how they differ from analytical solutions, rather than on the method?

I imagined the bar slipping along a virtual displacement, with the top and the bottom slipping by equal amounts. Since the planes are orthogonal, I took the components of these displacements: the lower end is displaced Lsinα in the direction of the right plane and by Lcosα in the direction of...

All I need is for someone to look at my schematic and tell me if this circuit will work. Thanks.

I don't have an idea of where to start. I tried to do Ein = 1/2 mv^2 ------ (1/2)(1)(10)^2 ----------- 50 but i don't know where to go from here

The answer in the textbook says 0J but I am not sure what the concept behind it is. Does it have something to do with gravity?

When a charged particle moves in a magnetic field, the magnetic field will not work. But when a nail flying over a permanent magnet is attracted by the magnet, the magnet does work on the nail. Can anybody explain why this is so?

I would be glad to know if there is evidence of the efficiency of physiotherapy based on magnetism.

Missed units in the photo - J Answer is 110 000 J

So, the Cp and Cv its very confusing for me. But, i understand what's its happening in this process, so, i use the logic and first i obtain a ecuation for obtain the final temperature ecuaticon: Q=m*C*△T Q=m*C*(T2-T1) T2=(Q+T1)/(m*C) If the process its in constant pressure, i use the Cp valor...

Hey guys! This is problem from Callens Thermodynamics textbook and I'm stuck with it. My goal was to get a expression for the entropy ##S## which is dependent on ##T## so I can move into the ##T-S##-plane to do my calculations: I startet by expressing the fundamental equation as a function of...