Work done Definition and 1000 Threads

When we calculate the work done by a force applied on an object (suppose force and movement are in the same direction and a constant force) do we take into account the relative distance ot the absolute distance. When saying relative distance i mean if the object is moving on top of a platform...

Homework Statement How much work per step per leg in the race? How much work must he (single leg) squat to equate 1 step of work in the race? The given variables are: Displacement: 100 meters Time: 9.65 seconds runners weight in kg= ? 100 steps to complete 100m race, alternating legs...

Homework Statement [/B] A force acts on an object along an x axis. The force varies with position as shown in the graph below. On the graph, F = 52.0 N. Find the work done by the force as it moves the object from x = 0 to x = 15.0 m. Homework Equations [/B]The Attempt at a Solution So what...

Homework Statement A grocery cart with mass of 19.3 kg is pushed at constant speed along an aisle by a shopper who exerts a force of 13.1 N on the cart at an angle of 18.3 from the horizontal. The aisle is 15.1 m long. The coefficient of friction is 0.0658. Find the work done on the cart by...

Homework Statement A spiral staircase in a building is in the shape of a helix of radius 5 meters. Between two floors of the building, the stairs make one full revolution and climb by 4 meters. A person carries a bag of grocers up two floors. The combined mass of the persona and groceries is 70...

Homework Statement What is the minimum work needed to push a 1000-kg car 300 m up a 17.5 degree incline? A. Ignore friction B. Assume the coefficient of friction is 0.25 Homework Equations W = F*d Net force = ma The Attempt at a Solution At first I did: Work = F*300*cos17.6 but I later...

Homework Statement This is a lab I did for physics. In this experiment, a glider starting from rest on an air track is attached to a string. The string is drawn over a pulley with a mass hanger tied to the other end. Work is done by gravity which results in a gain of kinetic energy of the...

Homework Statement x1= -2, x2= 2 F1= 1, F2= -2 Graph in uploaded image Homework Equations w= F* del x* cos(theta) The Attempt at a Solution I am trying to find the area under the points of F and x but it has an irregular shape and i don't know what to do? Should i do w= (f1-f2)(del x)?[/B]

Homework Statement The 4-kg ball and the attached light rod rotate in the vertical plane about the fixed axis at O. If the assembly is released from rest at and moves under the action of the 60-N force, which is maintained normal to the rod, determine the velocity v of the ball as approaches ...

In the given question part (a) I don't understand why the work done is negative? The answer says that the displacement is along positive x direction (i understand that) while force acting on the particle is along negative x direction ( why is that? since it appears that as the value of x is...

1. The problem statement, all variables, and given/known data How much work does gravity do on a 1.9-mg raindrop as the drop falls to the ground from a cloud 2500 m above the ground? Homework Equations W = FΔx F = ma The Attempt at a Solution I thought this problem would be pretty...

Homework Statement If you apply a force F with the x component =-6.97 N and the y component = 8.47 N on a car which moves along the x-axis by a displacement of 3.37m. What is the work done on the car by your force in J? Homework Equations W=Fxd The Attempt at a Solution I think that the...

Why does it cost roughly the same effort to run against an inclined treadmill as up a hill of the same inclination? That is neglecting the movement of the legs and the bobbing up and down as we run and the wind resistance. I remember being told in school physics that there is no work done unless...

Homework Statement Given electric field ##\vec E = 6x^2\hat i +6y\hat j+4\hat z## v/m Find ## V_{MN}## if both M and N separate by M(2,6,-1) and N(-3,-3,2) Homework Equations The Attempt at a Solution here i find ##V_{MN}## by unit vector from N to M is ##\frac 1 {\sqrt (115)}(5\hat i +9\hat...

Homework Statement Consider a rope of mass M and length L, resting on a horizontal table, as shown in the figure. The coefficient of kinetic friction between the table and the rope is μk. Let's consider the work that's done by friction as we slide the rope off the table. a.) Consider a small...

Homework Statement I have two objects that slide without friction on a circle of radius R, oriented in a vertical plane, as seen on the attached photo. The heavier object (mass = 3m) is attached to a spring with an unstretched length of zero and spring constant k. The fixed end of the spring...

If we have two objects forming an isolated system and their centre of mass is ##X_{com}##, we know by work energy theorem that work done on centre of mass will be ##\int F_{ext}.X_{com}= 0## as no external force is acting on the system. However, if there is internal forces between the objects...

My book says: "Let us derive an expression for the potential energy associated with an object at a given location above the surface of earth. Consider an external agent lifting an object of mass ##m## from an initial height ##y_{i}##above the ground to a final height ##y_{f}##. We assume the...

Hi there, i am struggling with the following problem. Air is pumping into a bottle with volume V and pressure Pi until it reaches a final pressure Pf. The temperature remains the same during the process and the gas is an ideal one. We have to calculate the work that is done. I am not quite...

work done in taking positive charge from A to B in electric field E= potential energy at B - potential energy at A OR potential at A-potential at B Am i correct in both formula?

Homework Statement An imperfect gas obeys the equation (p+\frac{a}{V^2_m})(V_m-b)=RT where a = 8*10^(-4)Nm^4mol^(-2) and b=3*10^(-5)m^3mol^(-1). Calculate the work required to compress 0.3 mol of this gas isothermally from a volume of 5*10^(-3)m^3 to 2*10^(-5)m^3 at 300K. Homework Equations...

Friction is said to be a non conservative force. And I see various sources state that work done by a non conservative force on a round trip is always non zero. But is that always true? In a case where a coin is placed on a turn table, and the table is rotated, and the coin does not move during...

How come ##adiabatic \,work = C_v(T_2 -T_1)##

Sorry,i want to ask a question here the note said the volume is "fixed" here. if the volume if fixed,how comes the work done(because no change of volume) here i totally get lost here thank

A force F = -K(yi + xj) (K is a positive constant) acts on a particle moving in the x-y plane. Starting from the origin, the particle is taken along the positive x-axis to the point (a, 0) and then parallel to the y-axis to the point (a, a). What is the total work done by the force F on the...

<Moderator's note: Moved from a technical forum and thus no template used.> Consider a gas in a closed container with a piston allowed to move. Let's start with a volume of 15 and pressure of 1.5. We add heat to the system, let's say 1200 J. This forces the piston to move increasing the volume...

Hey How can i calculate the work done by a homogeneous electric field on a positive charge q = 7 × 10^-8 C when the charge moves from point 1 to point 2 . I have two cases: a) the charge is parallel to the Electric field; b) the displacement of the charge takes place at the angle α = 60 ° to...

[Mentor's note; thread title edited to be more descriptive] If I push a 2000 lb car 100 feet slowly across the parking lot say taking 10 minutes to do it, and later do it again this time taking 2 minutes to do it, will I have used approximately the same amount of total force to accomplish both...

My question is:why is small work done,dW taken as F.dx instead of x.dF because integrating the latter should also give the same result(taking x out of the integral and integrating dF gives x (F) ).Visualising this integration graphically seems to suggest the same. Similar is the case with...

Given that in a Carnot Cycle the two adiabatic processes are essentially equal and opposite in magnitude the total work done by the cycle is in the two isotherms. The total work of the system is generally given as -NR(Th-Tc)ln(Vb/Va). Does this mean that the work done by a monatomic ideal gas is...

Homework Statement I am trying to calculate the theoretical time that it takes for a small piece of aluminium foil on a bottom plate to reach a top plate. The plates have a potential difference created by a 3kV Cockcroft–Walton generator. The plates are short cylinders with a surface area of...

Homework Statement I have the data for a p-v diagram from experiment of a fluid (the fluid is unknown). The data is attached below as the crosses. It also has the approximated ideal cycle for that data. Does anyone know how to find the work done for this real experimental data? Maybe a MATLAB...

Homework Statement http://i.imgur.com/TdPWVgr.pngHomework Equations WD=mgh The Attempt at a Solution mass per length=0.8kg/m mgh= ∫(0,10)(0.8g(10-y))dy=[8gy-0.4y^2g](0,10)=80g-40g=40g However, the answer is 20g whats wrong with my calculation? thanks

Homework Statement Homework Equations PV = nRT \\ W = - \int_{V_i}^{V_f} P dV \Delta E_{int} = Q + W The Attempt at a Solution a)[/B] Since this is a cyclic process, the change in internal energy of the system is 0. \Delta E_{int} = 0 The process causes some ice to melt, meaning heat...

Is the work done by a constant voltage source positive or negative when current is opposite to emf?

Homework Statement A 5.72 kg block is released from rest on an inclined surface. The incline makes an angle of 25.0 degrees relative to horizontal. The block is known to be traveling at a speed of 1.33 m/s after sliding a distance of 2.60 m along the incline. How much work was done on the block...

Homework Statement a) [/B]There is a piston-cylinder arrangement; initial pressure is 200 kPa, initial volume is 0.04m^3. Volume of the gas increases to 0.1 m3 while the pressure remains constant, ie a constant pressure process. Calculate the work. b) There is a piston-cylinder arrangement...

I came across this website and I intend to find out more about work done by gravity and derivation of gravitational potential energy (Sorry, the thread name is too long, so I abbreviate it as G.P.E.) Ok, here is the problem. I am quite confused with the calculation of work done against gravity...

Homework Statement : [/B]Find the change in internal energy of 2kg water as it is heated from 0°C to 4°C. The specific heat capacity of water is 4200J/Kg and its densities at 0°C and 4°C are 999.9 kg/m3 and 1000kg/m3 respectively. Atm pressure=105PaHomework Equations :ΔU= Q-W W=PΔV M/V=D[/B]The...

Homework Statement An object is subject to a nonconstant force f = (6x^3 -2x) ihat such that the force is in Newtons when x is in meters. Determine the work done on the object as a result of this force as the object moves from x = 0 to x = 100 m Homework Equations w = f * d The Attempt at...

Homework Statement The drawing shows three situations in which a block is attached to a spring. The position labeled "0 m" represents the unstrained position of the spring. The block is moved from an initial position x0 to a final position xf, the magnitude of the displacement being denoted by...

Homework Statement : [/B]A thermally insulated closed copper vessel contains water at 15°C win the vessel is shaking vigourously for 15 minutes the temperature rises to 17°C the mass of the vessel is hundred gram and that the water is 200 g capacities of copper and water for 20 J/kg K and 4200...

Homework Statement A spring (k = 500 N/m) supports a 400 g mass in a vertical position. The spring is now stretched 15 cm and maintained at the stretched position. How much work is done in stretching the spring by 15 cm? Is this work dependent on the magnitude of force applied while stretching...

Hello. First, look at the figure describing Carnot's cycle. In 1st step (A → B) and 2nd step (B → C), I fully understand that the work done on the pistol (surrounding) by the gas (system) is dW = pdV where dV = Adl since F = pA is the only force on the pistol from the gas (I assumed there...

Dear Experts, Trying to analyze the work done by internal forces in a very simple two particle system which is attracted to each other with a constant force, i performed calculations based on two frame of references, 1.The center or mass frame of reference and 2. Frame of reference of one of the...

Homework Statement A man is standing on a cart of mass double the mass of man. mass of the man is m. initially the cart is at rest on a smooth ground. now, the man jumps w/ velocity v horizontally towards right wrt the cart. find the work done by the man during the process of jumping. Homework...

In a classic problem where a man walks along the length of a boat floating on the surface of water without friction, Should the net work done due to static friction between the man and the boat be zero. If the length of the boat is L, its mass being M, and the mass of the man being m, the...

Homework Statement The membrane around a cell normally has layers of charge that create a potential difference between its outer and inner surfaces. This difference is about 72 mV . When a singly ionized potassium ion moves through a channel in the membrane passing from the outside to the...

Homework Statement The problem is that a Carnot contains Boiling water in the hot reservoir and ice water in the cold reservoir. Given that 0.0400kg of ice is melted in 5 minutes, what is the amount of work done by the engine. Homework Equations Qh/Qc=Th/Tc W=Qh-Qc W=(1-Tc/Th)Qs q=mHf...

If magnetic force does not exert work on moving charges, how could a current loop immersed in a magnetic field rotate and how could a magnet attract or repel another one?