Work problem Definition and 158 Threads

Homework Statement A 4.00-m length of light nylon cord is wound around a uniform cylindrical spool of radius 0.500 m and mass 1.00 kg. The spool is mounted on a frictionless axle and is initially at rest. The cord is pulled from the spool with a constant acceleration of magnitude 2.82 m/s2...

Homework Statement Calculate the gas' mechanical work on its environment for the thermodynamic process path IF. Solution says: 505 J Homework Equations W=\int_i^f p,dv i = Vi, initial volume f = Vf, final volume The Attempt at a Solution My approach is to find a...

1. Problem statement and all known/given variables 2. Related equations W = fd Newtons kinematic equations 3. Attempt at solution For part a) since the magnitude of the work done by gravity to 2 a.u is 2500GJ I use the equation W = fd and I solve for f by dividing work by the distance 2500...

Homework Statement A 10 kg block lies on an incline 15 degrees above the horizontal. A force F, parallel to the incline, pushes the block up the incline. There is a displacement of 7m and the displacement is done with constant velocity. Given that the coefficient of kinetic friction, μ, is...

Homework Statement A force F=12NÎ-10NĴ acts on an object. How much work does this force do as the object moves from the origin to the point R=13mÎ+11mĴ? Homework Equations Work is the product of Force and Displacement (W=F*s) The Attempt at a Solution Things I know, or think I know: The object...

The problem: If two electrons are held at fixed points (5,0) and (-5,0), respectively, find the work done in moving a third electron from the origin to (3,0) All equations: Force of repulsion between two electrons: \begin{equation} \frac{1}{d^{2}}. \end{equation} \begin{equation} W =...

Question about maximum Kinetic Energy?? KE & Work problem?? A 1.5 kg block is initially at rest on a horizontal frictionless surface when a horizontal force along an x-axis is applied to the block. The force is given by F(x) = (2.5 - x^(2))i N, where x is in meters and the initial position of...

Homework Statement A truck is traveling at 11.1 m/s down a hill when the brakes on all four wheels lock. The hill makes an angle of 15.0° with respect to the horizontal. The coefficient of kinetic friction between the tires and the road is 0.750. How far does the truck travel before coming to...

Homework Statement A 31.3 kg sled starts at rest on a horizontal road. The coefficient of kinetic friction between the sled and the road is μk = 0.23. A man pulls the sled a distance 8.75 m along the ground by exerting a constant force of magnitude 257 N on a rope that makes a 23.7o angle...

Sorry for the second post, but I want to know how to solve such problem when it comes to this situation. Homework Statement A vertical rope is used to lower a block of mass M = 48.3 kg at a constant acceleration of magnitude a = 1.54 m/s2. Find WT, the work done by the tension in the cord...

Homework Statement A highway goes up a hill, rising at a constant rate of 1.00 m for every 40 m along the road. A truck climbs this hill at constant speed v_up = 18 m/s, against a resisting force (friction) f equal to 1/20 of the weight of the truck. Now the truck comes down the same hill...

A 2000lb elevator travels from the ground floor to the 1st floor and on to the 9th floor. At the 1st floor, a 100lb person gets off, on the 2nd floor a 110lb person gets off, on the 3rd floor a 120lb person gets off and so on and so on till the last person gets off on the 9th floor. a) How...

Homework Statement A body has rest mass of 10^5 Kg. Find how much work must be done on the body to give it a velocity such that the clocks on the body run at 1/10 of the rate of the lab clocks. compare the work energy with the rest energy of the body Homework Equations γ=1/√(1-(v/c)2)...

Homework Statement A well is dug in the shape of a rectangular prism. It is 30ft deep and has a base with area of 40ft^2. Assuming that the soil weighs 150 lbs/ft^3, calculate the work W required to raise the soil to ground level. Homework Equations W = ∫dW dW =...

Homework Statement You apply a constant force F=(-68.0N)i + (36.0N)j to a 390kg car as the car travels 60.0m in a direction that is 240.0° counterclockwise from the x-axis. How much work does the force you apply do on the car? Homework Equations W=Fs W=K2-K1 W=Fcos(θ)s F/m=a...

PROBLEM 1 Homework Statement The frame in the figure is supported by a hinge in A and a roller in G. It is loaded by a couple = 14 kN*m in B, a force = 12 kN in D and a distributed force = 4 kN/m on section EG. = 1.4 m. Calculate the normal force in C. Use the correct signs...

1. A 20.0 kg dog stands on a frictionless inclined plane. A constant upward 60.0 N force parallel to the incline is applied to the butt of the dog. As a result the dog slides upward 12.0 m along the surface. (a) What is the component of the applied force in the direction of the motion? (b) How...

Homework Statement The two masses in the Atwood’s machine shown in Figure 8–23 are initially at rest at the same height. After they are released, the large mass, m2 falls through a height h and hits the floor, and the small mass, m1rises through a height h. Find the speed of the masses...

I have a question with process when using D'Alembert/Virtual Work. I have the example question: A uniform plank of mass M is leaning against a smooth wall and makes an angle α with the smooth floor. The lower end of the plank is connected to the base of the wall with a massless inextensible...

While driving my 1,500kg car at 18 m/s, I unexpectedly see a stop sign and must brake hard. How much work must be done on the car to stop it? I used KE=1/2(mv2) I came up with the answer of 243,000 J, but my professor gave me only 5 out of 10 points for the answer...any one see where I went...

Trig work problem... (am I correct?) Homework Statement If we call the height @ which the supports cross ,x, express this height as an equation in terms of H1 and H2 Only... Use similar triangle... Are my proportion correct? x/H1 = (L1-L)/L1 x/H2 = (L)/L1 = (L1-L)/L1 Because Where...

Homework Statement Explorers in the jungle find an ancient monument in the shape of a large isosceles triangle . The monument is made from tens of thousands of small stone blocks of density 3 174 kg/m3. The monument is 17.6 m high and 69.4 m wide at its base and is everywhere 3.30 m thick...

Homework Statement A block of mass 3 kg, which has an initial speed of 6 m/s at time t = 0, slides on a horizontal surface. Find the magnitude of the work that must be done on the block to bring it to rest. Answer in units of J. Homework Equations F=MA W=FD Kinematics Vf=Vi=AT...

Homework Statement This is generalized from problem # 11.52 from "Physics: For Scientists and Engineers: A Strategic Approach" By Randall D. Knight 2nd Ed. An (M) kg weather rocket generates a thrust of (F) N. The rocket, pointing upward, is clamped to the top of a vertical spring. The...

Homework Statement The graph below shows the component (Fcos(theta)) of the net force that acts on a 5.0 kg block as it moves along a flat horizontal surface. Find (a) the net work done on the block and (b) the final speed of the block if it starts from rest at s = 0. The graph shows...

Homework Statement An amusement park roller-coaster of height h has a loop-the-loop of radius R. A frictionless car starts at the top. Find its speed at each of the points a, b, c. Find the normal force (vector) exerted on it at points a and b. Find the minimal h-to-R ratio that will...

Homework Statement The force required to stretch a Hooke's-law spring varies from 0 N to 70.7 N as we stretch the spring by moving one end 6.52 cm from its unstresses position. Find the force constant of the spring. answer in units of N/m. Find the work done in the stretching the spring...

Homework Statement 2 particles of masses M and m are initially at rest and infinitely separated. When they move towards each other due to gravitational attraction, what is their relative velocity at any instant? Homework Equations The Attempt at a Solution The problem may be...

Hello! I've been a long-time follower of the Physics Forums and have found it to be a great resource for a variety of physics and engineering topics, although I have not actually felt compelled to create an account on the boards until today. I have encountered a difficult thermodynamics problem...

Homework Statement Can the normal force on an object ever do work on the object? Explain your answer. The answer in the textbook is: The normal force can do work on an object. For example, when you jump, you push down on the ground and the normal force pushes up on you and...

Homework Statement A small block is placed at height h on a frictionless ramp inclined at an angle theta. Upon being released, the block slides down the ramp and then falls to the floor (a distance y below the base of the ramp). A small hole is located a horizontal distance x from the end...

Homework Statement Joe exerts a force of 300 Newtons to move his car, which has run out of gas. How much work has he done if he moves the car 200 meters in 3.0 minutes? Note that the car weighs 10000 Newtons. Homework Equations W=F\DeltaXcos\theta W=work F=force \DeltaX=change...

Homework Statement Suppose a worker pushes down at an angle of 30° below the horizontal on a 30.0‐kg crate sliding with along a horizontal warehouse floor (μ_{k} = 0.25) for 4.5 meters. a. What magnitude of force must the worker apply to move the crate at constant velocity? b. How much...

Homework Statement You drag a(n) 15.8 kg steamer trunk over a rough surface by a constant force of 90.9 Nacting at an angle of 28.6? above the horizontal. You move the trunk over a distance of22.8 m in a straight line, and the coefficient ofkinetic friction is 0.18. The acceleration of...

Homework Statement A = 2i - 3j + 3k B = 4i +2j + k C = i + 2j - 2k a) Find the work done by force A to move an object C b)Find the work done by the forces A and B acting together that moves an object C c)Suppose point O is defined at the tail of C. Find the moment of force A applied...

Homework Statement PART A: A force ~F = Fx ˆı+Fy ˆ acts on a particle that undergoes a displacement of ~s = sx ˆı + sy ˆ where Fx = 6 N, Fy = −3 N, sx = 5 m, and sy = 1 m. Find the work done by the force on the particle. Answer in units of J. PART B: Find the angle between ~F and...

A 10-ft chain weighs 24 lb and hangs from a ceiling. Find the work done in lifting the lower end of the chain to the ceiling so that it is level with the upper end. since you just take a little piece and add them up through an integral wouldnt it be the integral from 0 to 10 of 2.4x...

Homework Statement Hickey reached a speed of 35 m/s on his skateboard . Suppose it took 21,000 Joules of net work for Hickey to reach this speed from a speed of 25 m/s. Find Hickey's mass Homework Equations Work = Force x Distance Cos(theta) The Attempt at a Solution From my...

Homework Statement A catcher "gives" with a baseball when catching it. If the baseball exerts a force of 511N on the glove, so that the glove is displaced 12.0 cm, how much work is done by the ball? Homework Equations W=F* \Deltax [b]3. The Attempt at a Solution [/tex] W=511*12.0?

Homework Statement A spring (k=600 N/m) is at the bottom of an inclined plane that makes and angle θ=30° with the horizontal. The spring is compressed by 0.10 m and a block of mass M=2.0 kg is placed against it, as shown below. The block is then released from rest. a) Determine the speed...

Homework Statement While doing a chin-up, a man lifts his body 0.40 m. Homework Equations Us = mgh W = Fd a) How much work must the man do per kilogram of body mass? b)The muscles involved in doing a chin-up can generate about 70 J of work per kilogram of muscle mass. If...

Homework Statement - A book has a weight of 21N. It falls off the shelf on to the floor, 3 m below. The work done by the force of gravity is what? - A book has a weight of 21N. You pick it up off the floor, and return it to the shelf, 3 m above. The work done by the force of gravity is...

Homework Statement A slide similar to der stuka is 35.0 meters high but is a straight slope,inclined at 45.0 degrees with respect to the horizontal. If a 60kg woman has the speed of 20.0m/s at the bottom and the work done by frictional force on the woman is -8.58 x 1000J, find the magnitude...

Homework Statement Moving a 150kg fridge a 12m ramp with a rise of 2.4m. the mover pulls the ridge up with a constant force of 710 N. the acceleration due to gravity is 9.8 m/s^2 Homework Equations W=Fs F=ma The Attempt at a Solution I found out the angle of the ramp was by...

Homework Statement a 3kg block moves initially at 4 m/s at t=0 and slides on a horizontal surface... Find the magnitude of word that must be done on the block to bring it to rest Homework Equations I believe we must use the equation w=Fs The Attempt at a Solution I drew the free...

A cylindrical reservoir of diameter 4 feet and height 6 feet is half-full of water weighing w pounds per cubic foot. Find the work done in emptying the water over the top. i put the cylinder on the x-y axes, so y represents height and x represents radius of the cylinder. so the volume of a...

Homework Statement n Figure 7-32, a constant force of magnitude 82.0 N is applied to a 3.00 kg shoe box at angle f = 53.0°, causing the box to move up a frictionless ramp at constant speed. How much work is done on the box by when the box has moved through vertical distance h = 0.150 m...

Homework Statement a .50 kg ball thrown upward has an initial Kinetic energy of 80 J. Homework Equations (a)what are its kinetic and potential energy when it has traveled 3 quarters of the distance to its maximum height? (b) speed at this point? (c) potential energy at the maximum...

Homework Statement A 3.0 kg body is at rest on a frictionless horizontal air track when a constant horizontal force acting in the positive direction of an x-axis along the track is applied to the body. A stroboscopic graph of the position of the body as it slides to the right is shown in...

Sam works at an amusement park. A boat of children on a water ride comes the the pier at the end of the ride. They are moving at a constant speed of 1.2 m/s, and the loaded boat has a mass of 1200kg. Sam slows the boat down by pushing on it until it comes to rest at the pier. If he stops it in a...