Work done Definition and 1000 Threads

Homework Statement The force on a particle is directed along an x-axis and is given by F = F0(x/x0 - 1). Find the work done by the force in moving the particle from x = 0 to x = 2x0 Homework Equations The Attempt at a Solution It looks like the force is a recurrence relation or...

Homework Statement A skier starts from rest on a 20m high, 20° slope. μk=0.210 Find the horizontal distance traveled by the skier. From this, for the equations below we know that: yf = 0 vi = 0 vf = 0 Homework Equations Wnet = Wnc + Wg = ΔKE Wnet = -fkd Wnc = ΔKE + ΔPE Wnc = ΔKE + mg(yf - yi)...

Homework Statement What is the minimum work needed to push a 900 kg car 880 m up along a 9.5° incline? Assume the effective coefficient of friction retarding the car is 0.20. Homework Equations W = F * d * cos (θ) Normal Force - mg * cos (9.5°) Force of kinetic friction = μ * Normal Force...

Homework Statement A 265-kg load is lifted 24.0 m vertically with an acceleration =0.190 g by a single cable. Determine the work done by gravity on the load. Homework Equations Force of Gravity = mg W = F * d * cos (theta) The Attempt at a Solution I think I know why I did...

Homework Statement A 6.8-nF parallel plate capacitor with a sheet of Mylar (κ = 3.1) filling the space between the plates is charged to a potential difference of 160 V and is then disconnected. (The initial capacitance including the dielectric is 6.8 nF.) (a) How much work is required to...

Homework Statement I was asked to find the distance a particle had traveled and was given its integral solved, except the upper limit was an equation. (x^2+2x) is the force in pounds that acts on the particle Homework Equations \int_{0}^{x^2+2}(x^2+2x)dx = 108 The Attempt at a...

Homework Statement A train with a mass of 250 tonnes starts from rest and accelerates up an incline of 1 in 100 attaining a speed of 45 Kph after traveling 200m. If the frictional resistance to motion is constant at 30KN calculate the work done by the engine using the principle of conservation...

Ok here's the question: A body m is attached to a spring with spring constant k. While the body executes oscillations it also experiences a damping force F = -βv where 'v' is time derivative of displacement of the body from its equilibrium position. I believe equation of motion is F =...

Homework Statement I ask this because my initial assumption was that work done by a non-conservative force (friction in this case) is also equal to thermal energy. However, in my book, it gave an equation with W = Emec + E thermal. They also had an example where they added up the work and...

I need to calculate the work done by an electric motor when it has a pulley wheel on the end but nothing on the pulley wheel. I know work done = force x distance. And of course force = mass x acceleration. But I cannot for the life of me think of how I am going to work out the acceleration? or...

Homework Statement A 4.63-kg ball of clay is thrown downward from a height of 2.69 m with a speed of 5.01 m/s onto a spring with k = 1610 N/m. The clay compresses the spring a certain maximum amount before momentarily stopping. b) Find the total work done on the clay during the spring's...

Homework Statement We must apply a force of magnitude 80N to hold the block stationary at x = -2.0cm. From that position, we then slowly move the block so that our force does +4.0J of work on the spring-block system; the block is then again stationary. What is the block's position? (Two...

Homework Statement A 80-kg block is pulled across a rough surface a distance of 1.25 metres. How much work was done in moving it? The coefficient of static friction was 0.3 and kinetic friction was 0.2. Assume the velocities were very low. Homework Equations W = fd ?? The Attempt at...

Hi We all know that work done corresponds to energy used and calculated as force*distance So if we are pushing against a wall, it does not count as work done, as there is no motion However, aren't we still wasting energy when we are pushing against a wall? Since a certain amount of energy is...

Homework Statement Two point charges of magnitude +10 μC each are placed 0.2 m away from each other. a) How much work is done in placing the second charge? b) Is there any point at which the electric field and electric potential are both 0? Homework Equations Work = (charge of first...

Hello, I have become very confused after i tried to solve this question. A rope pulls a 2 kg object straight up, accelerating it from rest at 2.2 m/s^2 for 3 seconds. they want the work done by each force acting on it. Ok i found the displacement as 9.9 m up. Then i found out that the...

Homework Statement I want to start by saying that my instructor is a particle physics guy. He loves to talk about particles seems to want to rush through fluids and thermo so he can get to particles and the 'real modern physics.' He is skipping, skimming and not really covering a lot of this...

just a query about last part of a question. a mass m hangs at end of light string and is raised vertically by an engine working at a constant rate kmg.at t=o,velocity =0 x=0 and x is measured in upwards direction. now i have shown increase in total energy of the mass, when moved up a...

I learned Potential but could not understand what Potential Difference is. Some define it as Work Done per unit charge. I am confused what per unit charge is. Does that mean electrons or protons ? As much as I know, electric current is the flow of negatively charged electrons to the positive...

Hi all. I am trying to learn more on physics, and am at the subject on calculating work done. The formula to calculate work done is Work done = Force * Dislacement * consine(theta). I am on a question which explains: a 100N force is applied at an angle of 30 degrees to the horizontal to...

Homework Statement A fixed mass of an ideal gas undergoes a cycle PQRP of changes as shown in the following figure: Some energy changes during the cycle PQRP are shown in the following figure Complete the Figure Homework Equations Find the work done on gas from R to P The Attempt at a...

Homework Statement Homework Equations W = \int F dx For density of water i used D = 62.4lb/ft^3 g = 32.2 ft/s^2 g(D = \frac{m}{V}) gDV = mg gDV = F The Attempt at a Solution i use limit from 0 to 6 W = \int_{0}^{6} F dx W = \int_{0}^{6} gDV dx W = \int_{0}^{6}...

Homework Statement Problem with picture attached I need help on 24. **24 is a continuation of 23 so use the same dimension except for the distance... Or you can go here http://college.cengage.com/mathematics/blackboard/content/larson/calc8e/calc8e_solution_main.html?CH=00&SECT=a&TYPE=se...

Homework Statement A wagon is drawn by a student pulling with a constant force of F Newtons applied at an angle of θ° to the horizontal. If the wagon is drawn in a circle with radius r meters, how much work is done on the wagon? (I don't remember the actual numbers) Homework Equations...

Homework Statement Find the work done along the semicircle (x-1)2+y2=1 from the point (0,0,0) to (2,0,0) When F=r3cos2φsinφ\hat{r} + r3*cosφ*cos(2φ) \hat{φ}Homework Equations Work W=∫F*dr where dr=dr= dr\hat{r} + rsinφdφ\hat{φ} The Attempt at a Solution I convert the equation of the line...

[b]1. Find the work done by the force F=r3*cos2\varphi*sin\varphi*\hat{r} + r3*cos\varphi*cos(2\varphi) \hat{\varphi} from the point (0,0,0) to (2,0,0) Homework Equations Work=\int F*dr where dr= dr\hat{r} + rd\varphi\hat{\varphi}The Attempt at a Solution When muliplying the line element, dr...

Homework Statement What is the net work done if an object is raised 5m, carried horizontally 8m, lowered 2m, and then lowered 3m if there is no friction? Homework Equations W=F x d (force times distance) work done overcoming gravity: W=mgh (mass times gravity times...

Show that the work done by the driver plate during a stress accumulation phase is W=\frac{2m2g2fd}{k}(fs-fdI'm not sure where to start with this. I am given several equations but can't reach the desired equation. Fn=ρghA m=ρA3/2 θ=\frac{fs}{fd} X=\frac{xG}{2fsρghA1/2}...

Homework Statement a reservoir shaped like a right circular cone, point down, 20ft across the top and 8 ft deep, is full of water. how much work does it take to pump the water to a level 6ft above the top? Homework Equations The Attempt at a Solution so i placed the cone with the...

Homework Statement Calculate the work done by air, when it pushes water out of a barrel (cylindrical), that is 1m in diameter. The starting water level was 80 cm from the bottom of the barrel and the water level at the end was 20 cm from the bottom. The water was pushed out through an...

Homework Statement The figure shows a thermodynamic process followed by 130 mg of helium. How much work is done on the gas during each of the three segments? p_1 = 1.08 atm, p_2 = 5.41 atm, p_3=1.08 atm T_1=133 C, T_2=T_3=1760 C V_1=V_2=1000 cm^3, V_3=5000 cm^3 These are answers...

Homework Statement A particle of (positive) charge Q is assumed to have a fixed position at P. A second particle of mass m and (negative) charge -q moves at constant speed in a circle of radius r1, centered at P. Derive an expression for the work W that must be done by an external agent on...

It isn't actually homework, it was just a problem proposed and then the answer was also given, but I don't understand it and I would like some help in trying to understand. Homework Statement In a cylindrical container the water level is at 30 cm. If you float a glass bowl in it, the water...

Homework Statement A satellite in a circular orbit around the Earth with a radius 1.011 times the mean radius of the Earth is hit by an incoming meteorite. A large fragment (m = 83.0 kg) is ejected in the backwards direction so that it is stationary with respect to the Earth and falls directly...

Homework Statement An angler hangs a 5.50 kg fish from a vertical steel wire 1.30 m long and 4.32×10^-3 cm in cross-sectional area. The upper end of the wire is securely fastened to a support. Calculate the amount the wire is stretched by the hanging fish. (I found this to be 8.11x10-4 m)...

Homework Statement It takes 139 kJ of work to accelerate a car from 22.8 m/s to 27.7 m/s. What is the car's mass? Homework Equations Well, we know that work is also known as J and J is = to kg*m^2/s^2 so we can use the equation J = m(vf - vi) to solve this I think. The Attempt at a...

The work done by the frictional force on a surface in drawing a circle of radius r on the surface by a pencil of negligible mass with a normal pressing force N(co-efficient of friction μ) is ? my textbook says it is zero but i don't understand it why.

Homework Statement There are two infinitely long wires A and B, each carries a current of 1 Amp in the same direction. The two wires are 4m apart. a) Calculate the magnetic field created by the currents in the two wires at points C and D. Point D is 1m away from wire A and point C is 2m away...

Hi, just wanted to ask a simple question: In the following equation: Work done by gas = Pressure x Change in volume does pressure refer to the pressure of the gas (that is doing the work), or does it refer to the external pressure (i.e. pressure of the surrounding gas)? I've heard...

Homework Statement That's a graph of Force in Newtons (y axis) vs displacement in meters (x axis) for an object of mass 3.0kg that is moving along the x-axis and initially starts at rest. I am being asked to find the total work done on the object as it moves from x = 0 to x = 7...

Homework Statement "The work done by static friction can be: a) positive b) negative c) zero d) nonnegative e) any of the above Homework Equations W=F*d F(friction)= μ *FN The Attempt at a Solution I thought the answer must logically be "c) zero" because static friction has no distance...

what is wrong with this problem? http://www.cramster.com//answers-mar-10/physics/buoyancy-force-fig-14-36-spring-spring-constant-360x104-mis_811494.aspx In Fig. 14-36, a spring of spring constant 3.60x104 N/mis between a rigid beam and the output piston of a hydraulic lever.An empty...

Homework Statement A spring with a spring constant of 10 N/cm has a cage attached to one end (Fig. 7-53). Taking rightward as the positive direction, (a) how much work does the spring force do on the cage when the spring is stretched from its relaxed length by 7.6 mm? (b) How much additional...

Homework Statement A 5530-kg satellite is in a circular Earth orbit that has a radius of 1.81 × 10^7 m. A net external force must act on the satellite to make it change to a circular orbit that has a radius of 8.01 × 10^6 m. What work must the net external force do? Homework Equations...

Homework Statement Prove that the work done by an ideal gas with constant heat capacities during a quasi-static adiabatic expansion is equal to W= (PfVf)/(Y-1)[1 - (Pi/Pf)^((Y-1)/Y)] where Y = gamma, which is heat capacity at constant pressure over heat capacity at constant volume...

Homework Statement You have a level track. You push a cart with mass = 1.12[kg]. You measure the initial velocity to be 0.57[m s-1]. 2 seconds later, you measure the velocity to be 0.427[m s-1]. Homework Equations What is the work (reported in mJ) that friction did on the cart...

The question asks.. find the work done by Force (F)... the answer given was found by the x component of Force (F)... so my question is, is this the work done by Fx or by F?

Homework Statement A horizontal spring with spring constant 200 N/m is compressed 20 cm and used to launch a box across a rough horizontal surface. After traveling a distance it stops. What is the work done by friction force? Homework Equations W = F \cdot d KE_{spring} = \frac{1}{2}k \Delta...

Homework Statement An airliner of mass 300 tonnes is powered by four engines, each developing 15 000 kW. Its speed at take-off is 75 m(s^1), and it takes 11 minutes to reach its cruising speed of 210 m(s^1) at a height of 10 000 metres. Calculate the work done against air resistance during...

Homework Statement There is a closed, thermally insulated cylinder, separated into two chambers by a moveable, frictionless, gas-tight, thermally insulating piston. Initial, the volume of each chamber is 3 liters, and each contains an identical monoatomic ideal gas at pressure of 1 atmosphere...