Work done Definition and 1000 Threads

A certain insulating material has 5 x 1022 atoms, each having six degrees of freedom. It initially occupies a volume of 10-6 m3 at a pressure of 105 Pa. The pressure and volume are related by p(V - V0) = constant, where V0 = 0.94 x 10-6 m3Homework Equations W = -\int p\, dV PV = nRT...

Homework Statement We have a container/volume of 1m3 100 m below mean sea level, A pump connected to it, pumping from inside the volume with outlet in the surrounding water at same height. And there is an pipeline to air, with a one-way valve allowing air to be sucked down to the...

[Mentor's note: this post does not use the homework template because it was originally posted in a non-homework forum. It was moved here because it had already received some help.] ---------- Weiping lifts a rock with a weight of 1.0 N through a height of 1.0 m, and then lowers it back...

Homework Statement An initially deflated and flat balloon is connected by a valve to a storage tank containing helium gas at 1 MPa at ambient temperature of 20°C. The valve is opened and the balloon is inflated at constant pressure of 100 kPa (atmospheric pressure) until it becomes...

Consider a system with a spring and a block. The block moves on a frictionless surface. At the equilibrium position, the speed of the block equals to 0. Now i pull the block by a force F with a displacement of x. Assuming that the speed at the final position is v. Can you calculate the...

Homework Statement A carpenter is holding two tool boxes of mass 19kg and 21kg respectively. Calculate the work done to carry the tool boxes through a horizontal distance of 16m. Homework Equations W = mgh The Attempt at a Solution m = 21kg + 19kg g = 9.81ms^-2 h = 0 W =...

Homework Statement Find the work done by the force \vec{F}=6\hat{i}+8\hat{j} if the object starts from the origin, moves along the x-axis to the point (1,0), then moves in the y direction to the point (1,2). Find the work if instead the object moves diagonally from the origin to the point...

This question may sound weird but when we lift an object with a force equal to the weight of the object up to a certain height the Earth is doing negative work on the object as well. So shouldn't the net work be zero?

6.A person pulls a toboggan for a distance of 35.0 m along the snow with a rope directed 25.0° above the snow. The tension in the rope is 94.0 N. a) How much work is done on the toboggan by the tension force? Ok, so W = (F cos Θ) s = (94.0 cos 25°) 25 m = WRONG...

Where is the glitch? 1. Let a single free electron move along x-axis with constant speed Vx. It encounters magnetic field on its right side, so the Lorentz force accelerates it along y-axis and it gains speed Vy. --- Glitch or pass? 2. The electron does not slow down in x direction when...

when a magnetic field exert force on a moving charge the work done by it is 0.But bar magnet do work.And i read that magnetic field is a non conservative field so work done by it in a closed path is not 0.But in case of a moving charge it is 0 and magnetic field also store energy so it have the...

You are moving into an apartment and take the elevator to the 6th floor. Suppose your weight is 685 N and that of your belongings is 915N. (b) How much work does the elevator do on you alone (without belongings) on the downward trip, which is also made at a constant velocity? this is the...

Homework Statement A 2 m long chain of mass 4 kg rests on a table such that 60 cm of it hangs vertically downwards from the table. If the chain has uniform mass distribution, calculate the work done in pulling the entire chain upwards. Ignore the frictional force. Homework Equations...

Homework Statement A tank containing air is stirred by a paddle wheel. The work input to the paddle wheel is 9000 kj and the heat transferred to the surroundings from the tank is 3000 kj. The external work done by the system is ? Homework Equations dU = Q-W The Attempt at a...

my final is tomorrow and my instructor gave a list of questions that will be similar to the ones on the final exam and i want to see how they should be done properly. I've been working on other problems but i can't get past these ones. thanks a spring on a horizontal surface can be stretched 5m...

Definition/Summary Work is a measure of change of energy. The net work done equals the change in Kinetic Energy (this is the Work-Energy Theorem). Work is the integral of the scalar product (dot-product) of two vectors: Force and Displacement. "Displacement" means the change in position...

Does "work done" actually have any real meaningful sense or value? I've got no problem with "work done" when moving an object in a conservative field. This makes sense - you've got to put in energy when, for example, lifting an object in a gravitational field, and this energy is the work...

When two people have three candies each, the total number of candies is six, 2x3=6. So what does multiplication imply when we say work done = force x displacement? I know it's a dot product and the force is in the direction of the displacement.

Homework Statement This is a theoretical question that I do not quite fully understand. " An object moving up a 6m ramp to a height of 2m v.s vertically moving an object up 2m." Someone tell me the work done is the same for both scenario. How are they the same? Surely kinetic energy is...

The problem A 0.250 \operatorname{kg} block of cheese lies on the floor of a 900 \operatorname{kg} elevator cab that is being pulled upward by a cable through distance d_1 = 2.40 \operatorname{m} and then through distance d_2=10.5 \operatorname{m}. Through d_1, if the normal force on the block...

Homework Statement As per attachment. Part iii How would you do this question by integrating the work? Homework Equations W = - ∫P dV PV^gamma = constant The Attempt at a Solution So I integrated the work with P= constant/ V^gamma and came up with this: W = constant* (...

When a wire is placed in a magnetic field and current flows in that wire work is done on the wire and be calculated: 1) W = Fd 2) F = IL x B 3) W = ( IL x B )x d Must there be any derivations beyond what is above? If everything is "given" or... measured via instruments. Then...

Homework Statement Point charges, Q1 = +56 nC and Q2 = -98 nC, are placed as shown. In Figure 18.1a, an external force transports an electron from point A to point B. The work done by the external force is closest to: A) +620 eV B) -920 eV C) -620 eV D) +920 eV E) +770...

Homework Statement If someone is pushing an object up a ramp 2.6m long and 1.1m at the far end how do I calculate total work done? I know the force needed to push the object is 220N. Homework Equations Work Done = Force x Distance The Attempt at a Solution Do I do 2.6...

Here's the deal: You have an attractive potential like the gravitational one. -∫F.dr = U2 - U1 = ΔU If you go from U1 to U2, an external agent has to provide positive work against the direction of the Force Field. But your gravitational potential has to deliver negative work in order to...

I was just doing a read-through of my freshman griffith's electrodynamics textbook ( I found my comprehension of electrodynamics slipping again ... always gets me edgy ) and I find my self flummoxed yet again. So he goes through an example of magnetic forces lifting a weight, and shows how it's...

Homework Statement A 160 Newton box sits on a 10 meter long frictionless plane inclined at an angle of 30° to the horizontal as shown. Force (F) applied to a rope attached to the box causes the box to move with a constant speed up the incline. Calculate the amount of work done in moving...

Sorry if this question has already been considered in this Forum (I'm sure it is but I can't find it now). A rigid ball slide without friction in an horizontal plane and collide elastically with a wall, the plane of which is perpendicular to the ball's velocity. During the collision the ball...

Homework Statement Homework Equations W= ∫F.dr The Attempt at a Solution I'm fairly sure I've done the right thing, however my lecturer hasn't uploaded any solutions to any of these problems (which is ridiculous - how am I supposed to learn if I don't know when I'm right or...

NEVER MIND! I realized my question is kind of stupid. Its night here and I am kind of sleepy. :)) Homework Statement a battery of 4V is connected opposite to a battery of 2V to charge the 2V battery. assume the current running through the circuit to be 2 Ampere. What is the Work done by 1)...

w = ΔKE + ΔPE For a particle moving at constant speed, there is no change in velocity so no change in KE. What about change in PE for a partcile moving at constant speed on a equipotential surface? Would I be right in stating that since the particle moves along the same surface (AKA same...

Homework Statement The problem involves a container holding a gas at high pressure. The container is opened to the environment, where the gas will cool down, producing a liquid or solid, and I want to find the work done by the gas throughout this process. Homework Equations PV^γ = constant U...

I need some help understanding work. If a man lifts a box up to a shelf and a woman lifts the same box up to the same shelf in half of the time, who is doing more work? I understand that they're moving it the same distance but isn't the woman using more force because she is getting it to...

Homework Statement You have a sealed container with 2kg of water (molar mass: 18g/mol, density: 1000kg/m^3). The lid on the container is very light, and the container side walls are very tall, like a tall graduated cylinder. You start with the water at room temperature 25 C and boil all the...

Homework Statement A rope lifts a mass of 20kg vertically 80cm. How much work is done by the rope on the mass? How much work is done by gravity on the mass? Homework Equations W = FΔd Eg = mgh The Attempt at a Solution How much work is done by the rope on the mass? W =...

Can anyone help me solve this problem? It seemed straightforward at first, but I am not getting the correct answer of -12 Nm. Thank you! A nonlinear spring is modeled by a force law given by F(x) = -10x + 3x^2, where F is measured in Newtons and x in meters. How much work is done stretching the...

What is the work done on a paramagnetic? I have seen both of the following: \hat{d}w = -MdB \hat{d}w = -BdM Where B is magnetic field and M is magnetisation Am I missing something here or are these two completely opposite? My textbook says that -MdB is the work done but I am sure I...

Hi I am kind of Confused about an example in work done: It says that a man applies 250 N parallel to the slope to push a box up a slope for 3 m, Now I know that the formula for work done if Force by Perpendicular distance which is 250 x 3 = 750 (which is the correct answer in my book). The...

Homework Statement A gas initially occupying a volume V undergoes a sudden explosion, causing its volume to triple to 3V. Assuming that the pressure of the environment (atmospheric pressure po) remains constant, find an expression for the work done by the gas. Hint: Please notice that an...

Homework Statement As you are trying to move a heavy box of mass m, you realize that it is too heavy for you to lift by yourself. There is no one around to help, so you attach an ideal pulley to the box and a massless rope to the ceiling, which you wrap around the pulley. You pull up on the...

Hello, I am new. I hope that this is the correct place for this kind of question. I apologize for it being so long or annoying. Homework Statement An engineer that has a mass of 100kg has made an ideal mechanical advantage machine shown in the attachment. Platforms 1 and 2 are...

Hi, In what cases do I neglect the work done by the pump in an actual rankine cycle? I am reading that h5-h4 is negligible but in what circumstances do I accept this. Is this only for ideal rankine cycles? As I understand thermal efficiency is (work out + work in)/Heat in Thanks

Hello everybody! First of all, I would like to say that this is my first post in this forum, even though I've occasionally read some posts before. I'm a ChemE major from Mexico! I am currently taking Thermodynamics I, and I have trouble figuring out the expression: W = \int_{V_1}^{V_2} PdV I...

Homework Statement A block of mass m=18kg is pushed horizontally with a force of Fp=150N up an inclined plane of angle θ=32° and coefficient of friction of μ=0.10, a distance of x=5m. a) What is the work done by Fp. b) Work done by the gravitational force. c) Work done by the normal force...

Okay so please bear with me. I'm dying here. Here's a diagram of the situation I have. I set up the graph to be like so for what I would be rotating to get the volume. (Edit: I meant to put y = 2+1/5x) I'm really stuck here though. I know I need to pump the water to 11ft from it's current...

which kind of work is done while swimming? positive or negative? explain.

hi! so I'm in secondary two, and so far in my syllabus we have covered up to work done. now this is my homework, and I'm not sure whether my answer is accurate, could you help me with this? (I haven't learned the equations yet)

Hello all, In my physics textbook they discuss work done by ideal gas processes. The equation they give is Wgas = pΔV. I'm trying to figure it out if this is work done ON the gas by the surroundings, or work done BY the gas on surroundings. From a previous chapter, they presented the...

Homework Statement A force of ⃑ = 3.5 î+2.7 ĵ N acts on a 7.1 kg object over a displacement of = −2.2 î+3.9 j m in a time period of ∆t = 0.28 s. At what average rate is work being done? Homework Equations W= ΔKE Kinematic equations F=Ma W= Fd The Attempt at a Solution...

Homework Statement A 1kg box of Aluminum initially at 22C is warmed at P=1atm so that its T increases to 40C. Find a) The work done on the system Homework Equations W= -∫PdV The Attempt at a Solution The pressure is constant at 101,300Pa D=m/V So V=m/D D of Al at room...