Work done Definition and 1000 Threads

The question is as follows: An object of mass m=1 follows the trajectory: r(t) = 4 ln(t) i + 6t1/2 j + 2t k Calculate the force acting on the object and hence find work done between t=1 and t=2. I know that Force = Mass * Acceleration Therefore, F(t) = 1 * a(t) I also know that a(t) =...

I know that since gravity is a conservative force, the work done by it to displace an object some distance does not depend on the path taken. This leads to the conclusion that the work done by gravity in sliding an object down an inclined plane of height h would be ##mgh##. However, what is the...

Homework Statement From what I have seen on internet sources, the average force exerted by an falling object on the ground is equal to the work done by the ground to stop the object. Assume collusion is completely inelastic and object sticks to ground after impact. F: Net force on ground m...

Homework Statement In a needle biopsy, a narrow strip of tissue is extracted from a patient using a hollow needle. Rather than being pushed by hand, to ensure a clean cut the needle can be fired into the patient’s body by a spring. Assume that the needle has mass 5.60 g, the light spring has...

Homework Statement You hold a 500N barbell 0.5m above a level floor for 100s . During this time, the amount of work you do on the barbell is A 1000J B 0J C 500J D 50000J Homework Equations W = Fdcos(phi) The Attempt at a Solution F= 500 N d = 0.5 m Since the...

So we did an experiment calculating work (w=fd) by 1)running and 2)walking upstairs and it turns out that running and walking the same distace(d) with the same weight(f) makes the work done also the same. It later on becomes different when it comes to talking about power but for now let's stick...

Homework Statement Homework Equations KE = 1/2mv^2 f = -kx U = 1/2kx^2 Kinematic equations F = ma The Attempt at a Solution Horizontal components of the block's weight: 8.38N Compression of the spring: f = -kx 8.37 = -500x x = 0.01674 m , which is wrong and I would be grateful if someone...

Homework Statement A shopper in a supermarket pushes a cart with a force of 35.0 N directed at an angle of 25.08 below the horizontal. The force is just sufficient to balance various friction forces, so the cart moves at constant speed. (a) Find the work done by the shopper on the cart as she...

Homework Statement Two blocks have masses m1 and m2 and speeds v1 and v2. The objects slide directly toward each other along a frictionless horizontal surface and collide. After the collision, block m1 is at rest. Find the work done by the contact force on block m2 during the collision...

Why magnetic field never do work?

Hello, I'm having problems understanding what exactly is meant by a conservative vector field. So, allow me to explain how I currently understand it. Let \overrightarrow{F} be some sort of a vector field that is conservative. The stream plot of \overrightarrow{F} is shown below. From my...

1.what is the work done in an adiabatic compression process in a carnot cyclewhen we consider work done in efficiency why do we take heat exchange into account i.e.,qs-qrThe Attempt at a Solution

Suppose we have a carpet rolled (along it's length) into the shape of a cylinder (of radius R0). Now we allow the carpet to unroll to a radius Rf < R0. We can model the mass of the cylindrical part of the carpet as M = kR2 The differential work done by gravity would be dW = -MgdR = -kR2gdR This...

Homework Statement In a children's park, there is a slide which has a total length of 10 m and a height of 8.0 m . Vertical ladder are provided to reach the top. A boy weighing 200 N climbs up the ladder to the top of the slide and slides down to the ground. The average friction offered by the...

Homework Statement Homework Equations W = F d F = maThe Attempt at a Solution Constant Speed ==> a = 0 ==> Net Force = 0 ==> F cos 37 = mg sin 37 ==> F = 37.6 N sin 37 = h/d ==> 6/10 = 0.5/d ==> d = 5/6 W = F d = 5/6 * 37.6 = 31.3 N [Not In Choices] - Any Help?

Homework Statement Consider a non-conducting sphere of radius 'R' and charge 'Q' is enclosed by spherical shell of radius '5R' and charge '4Q'. If inner sphere is expanded to radius '3R'.Then amount of work done by the field in this process is Homework Equations W=ε0/2∫E2dτ The Attempt at a...

I'm trying to learn more about water electrolysis and the work done on and by the system, but I'm still very confused about a few elements. Knowing the volume of the closed container, the number of moles of water, the amps/volts from the battery, and the initial temperature of the water, I know...

Homework Statement Daniel Schroeder, introduction to thermal physics problem 1.36 (page 26): "In the course of pumping up a bicycle tire, a liter of air at atmospheric pressure is compressed adiabatically to a pressure of 7 atm. (Air is mostly diatomic nitrogen and oxygen.) a) What is the...

Homework Statement Three identical particles, each possessing mass m and charge +q, are placed at the corners of an equilateral triangle with side r. The particles are simultaneously set free and start flying apart symmetrically due to coulomb's repulsion forces. The work performed by Coulomb's...

If i lift it a distance x then bring it back down, so that the displacement is 0 but distance traveled is 2x. Will work done be doubled or will it be 0?

Homework Statement Homework Equations Conservation of Energy The Attempt at a Solution But it is not in the choices, Any Help?

Homework Statement Homework Equations W = F d The Attempt at a Solution W = F d 30 = F * 2 * cos 0 30 = 2 F F = 15 N [NOT IN CHOICES] !

Homework Statement A mass m1 = 5.1 kg rests on a frictionless table and connected by a massless string over a massless pulley to another mass m2 = 5 kg which hangs freely from the string. When released, the hanging mass falls a distance d = 0.83 m. Homework EquationsThe Attempt at a Solution...

Hi I am having trouble locating resources for a topic as I do not know exactly what it is called, and I am looking for assistance. If you wanted to look at human performance and calculate the various ways a human could perform a task and how this would affect outcome by including "work done"...

Homework Statement A charged particle is moved from a great distance to a distance d from a point charge. At distance d, the electric field has a strength E and a potential V. Which of the following represents the work done per unit charge q? Homework Equations F = Eq; V = Ed, E = kq/r^2; U...

Homework Statement A woman pushes a 38kg box on a horizontal floor with a force F⃗ that is directed 30° below the horizontal. The coefficient of kinetic friction between the floor and the box is 0.53. If the initial speed of the box is 7.89m/s and the box accelerates at 1.63m/s^2 , what is...

Can anyone please tell me where I am going wrong? I am getting the incorrect answer for the Word Done should be: WD = q(3x^2-6y) ... Apologies for not changing it into the format on here - but for my revision I have pretty much done that myself.

Homework Statement We did an experiment in class where a marble was released down a ramp and traveled a short distance before entering a hole inside an upside down cup, causing the cup to get displaced. Different masses were placed on top of the cup and the resulting displacements were...

I have a problem with question 4 part (iv) which is on here http://www.mei.org.uk/files/papers/m208ju_ail7.pdf Basically, I used Ep(initial) + Ek(initial) + W(Forward) = Ep(Final) + Ek(final) + W(Resistive) equation, where Ep is the potential energy, Ek the kinetic energy and W is the work...

Homework Statement The problem is asking to find the change in temperature of forged cylinder. I know how to calculate this, , however I am struggling to find the work done on the cylinder, which is required to solve this problem. The cylinder is annealed copper, which is compressed from a...

Homework Statement [/B] A mover pushes a 700 kg piano from rest up a ramp with a 9° slope. The piano is traveling at 2 m/s when it is 3 m above the ground. How much force does the mover exert on the piano?Homework Equations [/B] ##W = \Delta K##The Attempt at a Solution I started with the...

If I stand up on an accelerating bus, static friction between my shoes and the bus will do work. - I suppose it is negative work on the bus, and when velocity is constant it does no work at all, am I right? - does it do any work on me? - if I do not stand on my feet , but sit leaning my back...

Homework Statement A 250 gram rock is thrown with a speed of 30.0 m/s. It has a speed of 22.5 m/s just before it strikes the ground. Determine the work done by air resistance. There is also a diagram which yields more information. The rocks path is horizontal and it strikes the corner of a...

Homework Statement [/B] In climbing stairs that are 10.0 m high, how much work does a person weighing 60.0 kg do?Homework Equations [/B] W = FdThe Attempt at a Solution [/B] I know that when moving upwards, and when there is no change of kinetic energy from start to finish, the work done is W...

I'm having some trouble wrapping my head around a couple work concepts. I've been reading the following thread: https://www.physicsforums.com/threads/displacement-and-work.322461/ and I don't think I've fully grasped how work is accomplished. My first question is if I lifted a (w=3.0N) water...

Homework Statement a rigid body with a mass of 2 kg moves along a line due to a force that produces a position function x(t)= 4t^2, where x is measured in meters and t is measured in seconds. Find the work done during the first 5 seconds in two ways. Homework Equations x(t)= 4t^2 Work is ->...

Homework Statement In a closed system 0.4kg of gas at 374K is expanded isothermally and reversibly from 1MPa pressure to 300kPa. Given that Cv = 718j/kg and R = 287j/kg, determine the work done.[/B]Homework Equations Not sure? I guess W = p*V? The Attempt at a Solution I honestly don't know...

amount of work done by conservative force =amount of decrement in potential energy Is this correct?I think yes Because I have been told that Work done by non-conservative forces + work done by conservative forces = change in kinetic energy but Work done by non-conservative forces = change in...

I am having trouble understanding the concept of work on an intuitive level. The equation is rather simple but the definition of displacement is vague (everywhere I looked it's just stated as displacement of the body in the direction of motion). The question is, is this the displacement of the...

Hello, I picked up a challenging problem (at least to me) and I'm having difficulties. 1. Homework Statement An object moves in xy-plane from point O = (0; 0) to point A = (1 m; 0) and from there to point B = (1 m; 2 m). All this time when the object moves a force \vec F = ax2\vec i + by\vec...

Is work done in adiabatic process quasi static or not?

Stuck on part of this question regarding Cv value: I don't understand how one can get the value for Cv, I tried saying Cp - Cv = R (1) Cp/Cv = 1.5.so rearrange gives Cp=1.5Cv (2) Now sub 2 into 1 and that gives 0.5Cv = R But according to solutions that's wrong, Cv is 1010 and I can't get...

If an object moves in such a way that the point of application remains fixed then what can be commented on the work done by the force? (only qualitative analysis required)

1. The problem statement, all variables and given/Information If a person pushes a 28 kg object 1.2 m, how much work did they just do? Homework Equations W=Fd F=ma The Attempt at a Solution If W=Fd and F=ma, then W=(ma)d. The farthest I can get is W=28a*1.2=33.6a. Since the motion is...

Homework Statement Homework Equations The given elastic force equation The Attempt at a Solution I plugged in the numbers, with 0.2m for the change in s and 45 for a. Since I knew that work was equal to force * distance, I multiplied that result by another 0.2m. This got me 0.0144J, or...

If a neodymium magnet sticks over a steel plate and you want to separate them, it is advised to apply force such that the magnet slips over steel plate. So I was just wondering what would be the quantified decrement of this force as compared to the case when force is applied axially to separate...

1. Homework Statement Tis is my attempt to the question so far. I am not sure about the answers if anyone please confirm them whether I have done the solution correctly or not especially for part 1.4 and 1.6. Can anyone also guide me about how to do the last part. 1. A chargeQ =-10.0 nC is...

Homework Statement The volume of 30.0 moles of a monoatomic ideal gas is reduced at a uniform rate from 0.616m3 to 0.308m3 in 2h. Its temperature is increased at a uniform rate from 27.0◦C to 450◦C. The gas passes through thermodynamic equilibrium states throughout. (a) Write down explicitly...

Homework Statement A pump is required to lift 800 kg of water (about 210 gallons) per minute from a well 14.0 m deep and eject it with a speed of 18 m/s (a) How much work is done per minute in lifting the water? (b) How much work is done in giving the water the kinetic energy it has when...

Homework Statement A cylindrical container is sealed with a movable piston and contains 0.200 mol of oxygen. The initial pressure is 2.5 × 10^5 Pa and the initial temperature is 77◦C. The value of the ideal gas constant is R = 8.315J/mol · K. The oxygen, which can be approximated as an ideal...