Work done Definition and 1000 Threads

The question is like this: 8 charges of magnitude q and different sighs are placed at corners of a cube of side a. Find the work done in taking them far away from each other. Homework Equations U = kq1q2/r W = ΔU The Attempt at a Solution First i found out the potential energy...

Homework Statement A disc of mass m slides with zero initial velocity down an inclined plane set at an angle alpha to the horizontal; having traversed the distance l along the horizontal plane, the disc stops. Find the work performed by the friction forces over the whole distance, assuming the...

When a car is moving, the engine is transferring Chemical Energy to Kinetic Energy. He is doing work against the force of friction. If the force of friction is 210 N and the engine exerts a pull force for 10 M it transferred 2100J of Chemical Energy from its fuel to Kinetic Energy, considering...

I have a hard time understanding this concept: Work done is an energy transfer, for example: When I raise a book to a tall shelf, I am doing work against gravity. Energy is being transferred from Chemical Energy in my muscles to gravitational potential energy to the book. Right? In addition to...

Hello! I'm not sure if this should be in the physics section or chemistry, but I think it's covered in both. I apologise if this has been asked numerous times before! I am interested in the following adiabatic system, I think it counts as an isolated system: Here is my attempt to...

Hello. I have a question about a theoretical heat engine I recently encountered in my coursework: The setup is two chambers, one with more moles of a gas than the other, separated by a heat-conducting barrier. The right chamber has a small piston attached to it and is at a lower temperature...

A 4.0 kg block is dragged over a rough horizontal surface by a constant force of 20 N. The speed of the block increases from 3.0 m/s to 5.0 m/s in a displacement of 5.0 m. What is the magnitude of the work done by the friction force during this displacement? My work was the following: Ei...

A force of F = 35 N is used to drag a crate 7 m across a floor. The force is directed at an angle upward from the crate so that the vertical component of the force is Fv = 21 N and the horizontal component is Fh = 28 N as shown in the diagram. (a) What is the work done by the horizontal...

"Work Done by 2-D Force" What work is done by a force = ((1 N/m)x) + (4 N), with x in meters, that moves a particle from a position 1 = (2 m) + (3 m) to a position 2 = - (4 m) - (3 m)? I figured all I would have to do is find the displacement of the x and y coordinates after the force had...

Homework Statement Hello all, I need to find the change in internal energy (delta U) and work done (W) by an aluminum rod (from the expansion) as it is heated from 20C to 100C. Initial Length = 2m I found delta length = .00384m diameter = .01m radius = .005m...

Homework Statement The arrangement is as shown in the figure. Find the work done to increase the spacing between the wire and the loop from a to 2a. The Attempt at a Solution I calculated the potential energies in initial and final configurations using U=-M.B (all vectors) I got...

When calculating the amount of work done, using the force applied and the displacement, does the weight of the object do anything ?

Homework Statement I have a few questions I need help with on my assignment. I cannot wrap my head around this work and energy chapter. Anyway here it is; A 62.7-kg skier coasts up a snow-covered hill that makes an angle of 25.2° with the horizontal. The initial speed of the skier is...

Homework Statement A box of mass 6.0kg is accelerated from rest by a force across the floor at a rate of 2.0m/s for 7.0s. Find the net work done on the box. Homework Equations Work done = Force x distance The Attempt at a Solution F = ma F = 6 x 2 = 12N i solved for final...

We have a force which changes according to what point you're at, e.g: f=(4x²,3z-2y,2z), we need to calculate the work done by this force from point (0,0,0) to (2,1,3) on different curves I don't want an answer I just want an explanation for how this is done, this is what I understand so far...

Hi :D 1) Two equal masses (let a and b) are attached to the ends of a spring of spring constant k. The masses are pulled out symmetrically to stretch the spring by a length x over its natural length. The work done by the spring force on each mass is : (a)1/2kx2 (b)-1/2kx2 (C) 1/4kx2 (d) -1/4kx2...

Homework Statement Consider a parallel plate capacitor connected to a battery. You move the plates closer to each other. Will you do positive or negative work? The Attempt at a Solution As the plates are moved closer to each other, capacitance increases which increases the stored energy (V...

Homework Statement a box of mass 5.0 kg is accelerated from rest across a floor at a rate of 2.0m/s^2 for 7.0s. find the net work done on the box. Homework Equations f = ma w= fdcostheta The Attempt at a Solution f = ma f=10 w = fdcostheta w=10d w=10*v*t w=10*v*7...

Homework Statement A luggage handler pulls a suitcase of mass 17.1 kg up a ramp inclined at an angle 24.0 above the horizontal by a force of magnitude 146 N that acts parallel to the ramp. The coefficient of kinetic friction between the ramp and the incline is 0.257. The suitcase travels a...

here is the problem. w= f*d*cos(theta). theta is changing so it involves integration. i know the answer its about 52. i know one solution for it but i have been trying to figure out how to solve it integrating with respect to theta. the way i know to solve it is let cos(theta)= x /...

When a body falls from a height (h) under gravity,the work involved is mgh. How do you describe this work? Is it 'work done by the force (gravity) on the body' or 'work done by the body'. The confusion is, if work is done on the body the body gains energy; but if work is done by the body the...

Homework Statement A man in a wheel chair is being pushed up a slope, for a distance of 10 metres. He is moving at a constant velocity. What is the net work done when he reaches the top of the slope? Homework Equations W = FX The Attempt at a Solution I just seem to have...

Homework Statement A man wishes to pull a crate 15 m across a rough floor by exerting a force of 100 N. The coefficient of kinetic friction is 0.25. For the man to do the least work, the angle between the force and the horizontal should be: 0 14 43 66 76 Homework Equations...

I have a cuboidal object of dimensions 15cm x 7cm x 10cm. Its volume is 1050 cm3 Since density of water, is 1g cm-3, the object will have to weigh 1.05 Kg to sink. Assuming it sinks to the bottom and weighs 1.1Kg, and has to be lifted by 4, electric DC Motors. Will the motors have to...

A 1.6 kg breadbox on a frictionless incline of angle θ = 36° is connected, by a cord that runs over a pulley, to a light spring of spring constant k = 120 N/m, as shown in the figure below. The box is released from rest when the spring is unstrectched. Assume that the pulley is massless and...

Homework Statement Determine the amount of work done in firing a 2.0-kg projectile with an initial speed of 50 m/s. Neglect any effects due to air resistance Homework Equations W = delta K K = 1/2mv^2 The Attempt at a Solution just take K= 1/2(2)(50)^2 to get 2500...it seems...

Homework Statement A worker pushed a 26kg block 13m across a level floor at a constant speed, with a force directed 40 degrees below the horizontal. If the coefficient of kinetic friction between the block and floor is 0.40, what were a.) the work done by the workers force? and b.) the...

Homework Statement A 4.0-kg block is lowered down a 37° incline a distance of 5.0 m from point A to point B. A horizontal force (F = 10 N) is applied to the block between A and B as shown in the figure. The kinetic energy of the block at A is 10 J and at B it is 20 J. How much work is done on...

Homework Statement Hi I have a slight problem. Please comment on the question and solution. A car of mass 2 Tonnes arrives at a foot of a hill, traveling at a speed of 10m/s and reaches the top of the hill with a speed of 5m/s. The hill is 500m long and rises 1 in 125. If there is...

Homework Statement A force F = (4.37xi + 3.01yj) N acts on an object as it moves in the x direction from the origin to x = 5.06 m. Calculate the work done on the object by the force. Homework Equations dot product The Attempt at a Solution i took the dot product, FxDx+FyDy since there is...

Homework Statement A time-varying horizontal force is given by, F(t) = (1.00 t + 0.250 t^2) Newtons The force is applied from 0 to 5.00 seconds on a 10.0 kg mass which is initially at rest but is allowed to slide freely with only this one horizontal force acting on it. How much work is...

Homework Statement In the system shown in the figure, suppose the block has a mass of 2.7 kg, the spring has a force constant of 480 N/m, and the coefficient of kinetic friction between the block and the floor is 0.18. Find the work done on the block by the spring and by friction as the...

I know the integral to compute work done is (integral from a to b) F * dl where F and l are vectors, but I don't understand how I would use that in a problem. 1. Are a and b moments in time? 2. What is dl? Is that the same thing as l2-l1? So would it be (integral from a to b)...

1. Homework Statement An Ideal gas and a block of copper have equal volumes V and at the same temperature T and atmosphere pressure P. The pressure on both substances is increased reversibly and isothermally to 5P. a) Find the work done on the ideal gas if V = 0.5 m and T= 300 K P =...

A 330-kg piano slides 3.6 m down a 28º incline and is kept from accelerating by a man who is pushing back on it parallel to the incline. The effective coefficient of kinetic friction is 0.40 what is the work done by the normal force? If someone could let know how to find FN, would it...

Homework Statement Work done by conservative forces = -\DeltaU Homework Equations Above. The Attempt at a Solution Here is the whole equation: Wc+ Wnc = \DeltaK. Wnc = \DeltaK + \DeltaU. So, Wc = -\DeltaU. But, for example, how does that apply in a situation with no...

a box with a mass of 6.0 kg is accelerated from rest by a force across a floor at a rate of 2.2 m/s^2 for 5.9 s. Find the net work done on the box m=6.0kg a=2.2m/s^2 t=5.9 s a=0 degrees i know W=Fdcos(a) and F=ma so, F=6.0kg*2.2m/s^2=13.2N W=13.2N*d*cos0=13.2N*d I am a...

Homework Statement A worker pushed a 16 kg block 6.7 m along a level floor at constant speed with a force directed 32° below the horizontal. If the coefficient of kinetic friction between block and floor was 0.34, what were (a) the work done by the worker's force and (b) the increase in...

needs help with pressure and work done! Homework Statement if a 2 similar rocks are thrown down at different height, one at 100m and 1 at 200m, which one will exert more pressure on the floor? Homework Equations The Attempt at a Solution when i use f=ma, f in both cases are the...

A skier lowers a cart 30m down a slope with a sontant speed. The cart has a mass of 90kg. The angle of the slope is 60 degrees. The coefficient of friction is 0.100. A)Find the work done by friction as the sled moves down the hill. B) how much work is done by the rope on the sled. C) What is...

Homework Statement At a certain point, when a spring is stretched near its elastic limit, the spring force satisfies the equation F = −α x + β x3 , where α = 12 N/m and β = 890 N/m3 . Calculate the work done by the spring when it is stretched from its equilibrium position to 0.15 m...

Homework Statement A 4.0 kg object moving in two dimensions initially has a velocity V1 = (11.0i + 20.0j)m/s. A net force F then acts on the object for 2.0s, after which the object's velocity is V2 = (16.0i + 32.0j)m/s. Determine the work done by F on the object. Enter your answers...

Homework Statement In the figure, a constant external force P = 170 N is applied to a 20-kg box, which is on a rough horizontal surface. The force pushes the box a distance of 8.0 m, in a time interval of 9.0 s, and the speed changes from ν1 = 0.4 m/s to ν2 = 3.0 m/s. The work done by...

Homework Statement +1.0uC *-------3.0m---------*-----------3.0m---------* A B a) calculate the electric potential energy at A, 3.0m away from a point charge of +1.0uC. b) calculate the electric potential...

I have a physics teacher who is unable to explain anything if his life depended on it hence I am really struggling with physics. I am left out on a limb literally - at my wits end. I have this question that I have no idea where to start with. 2 villans slid a laundry basket containing a...

Homework Statement A block with mass 5.00kg, moves along the x-axis with zero friction. The block experiences a net force Fx that varies with it's position x. When x=0, v (initial speed) is equal to 2.0 m/s Find the work done on the block when it is displaced from x=0 to x=8 What is the...

Homework Statement Find the work done by nonconservative forces in stopping the plane. A 18000 {\rm kg} airplane lands with a speed of 92 {\rm m/s} on a stationary aircraft carrier deck that is 115 {\rm m} long. Homework Equations W = FD The Attempt at a Solution 18000 * 92 *...

Homework Statement Determine the work done in carrying a -2(micro C) charge from point p1(2,1,-1) to p2(8,2,-1) in the field E = axy + ayx a) along the parabola x = 2y^2 b) Along the straight line joining p1 and p2 Homework Equations W = F*dS = Fxdx + Fydy + Fzdz

Homework Statement You are pushing a refrigerator across the floor of your kitchen. You exert a horizontal force of 297 N for 6.7 s, during which time the refrigerator moves a distance of 2.8 m at a constant velocity. What is the work done by friction? Homework Equations W=fv...

Homework Statement One mole of a dilute gas initially has a pressure equal to 1.00 atm, and a volume equal to 14.0 L. As the gas is slowly heated, the plot of its state on a PV diagram moves in a straight line to the final state. The gas now has a pressure equal to 2.00 atm, and a volume...