Forces Definition and 1000 Threads

Homework Statement A group of construction workers are building a house and want to lower down an excess bundle of 1400 kg bricks to ground. They tie one end of a rope to the bundle of bricks, loop it through a pulley, and tie the other end of the rope to a toolbox. If the coefficient of...

Homework Statement A 0.140kg baseball traveling 35.0 m/s strikes the catcher's mitt, which in bringing the ball to rest, recoils backward 11.0cm. What is the average force applied by the ball on the glove Homework Equations F=ma; FAB=-FBA The Attempt at a Solution Not sure where to start for...

Hi, I don't really get what the point of volume forces is, if electromagnetism is a volume force. Its obviously no surface force, but in my opinion the definition says that its no volume force as well. The link below describes volume forces as "a force acting on all particles (volume elements)...

Homework Statement When a wood shelf of mass 7.7 kg is fastened inside a slot in a vertical support as shown in (Figure 1) , the support exerts a torque on the shelf. Assume that the slot exerts two vertical forces on the shelf, at points A and B. Determine the force exerted on the shelf by...

Homework Statement a pendulum of mass m and length L is pulled back an angle of θ and released. After the pendulum swings through its lowest point it encounters a peg α degrees out and r meters from the top of the string. The mass swings up about the peg until the string becomes slack with the...

Homework Statement I just can't seem to find anything that I can relate to for solving this problem and it's giving me a headache. I don't even know how to start solving this question. Please help: A man drags a package across the floor with a force of 40 N. The mass of the package is 10 kg...

If for say, I had a ''perfect object'' (Only mass with no dimensions) and I put three non-parallel and different pulling forces on the item, would these cancel themselves? After the doing the experiment myself with a non-perfect item, it seemed there was a slight advancement. The addition of the...

This is not a specific homework problem. It is a lack of understanding in theory relating to a lab report I have to write. We (my group and I) wrapped a 40 cm PVC pipe in copper wire (very densely and for almost the entire length), applied a current to it, and dropped a permanent magnet...

Homework Statement So we have 65N @ 30*, 30N @ 180* and 20N at 250* Homework Equations Ncos(angle)i + Nsin(angle)jThe Attempt at a Solution Using this video I did the following. F1(65N) = 65cos(30)i+65sin30i Then using the radian circle I saw that 30* has x,y coordinates of sqrt3/2...

Alright, so after looking at this video to do it I did the following. F1(65N) = 65cos(30)i+65sin30i Then using the radian circle I saw that 30* has x,y coordinates of sqrt3/2 and 1/2 respectively. So as shown in the video I did 65(root3/2)i+65(1/2)j = 56.3i + 32.5j I did this for the...

Homework Statement Problem # 1 Homework Equations Work done by several forces w=f * d cos theta w=mg n=w The Attempt at a Solution I can't figure out how to solve a) and b) NOT SURE: so my attempt a) f = mg = 30kg*9.8m/s^2 = 294N =magnitute of the force must the worker apply.(NOT SURE)...

Homework Statement Two metal spheres of equal radius ##R## are placed at big distance one from the other. Sphere 1 has total charge ##q## and sphere 2 has no charge. The two speheres are moved one towards the other until they touch, then they are moved again far away one from the other. What is...

I'm trying to understand couples, moments and forces. I know that a moment is a force causing a rotation about a certain point/axis. And I know a couple is a vector that represents the... and then that's where I'm trying to get clarification. Is a couple vector a representation of the general...

Homework Statement Hi, I have this problem: For motion under a pure (rest mass preserving) inverse square law force f = −αr/r3 , where α is a constant, derive the energy equation γmc2 − α/r = constant. Homework Equations E = γmc2 dE/dt = f.u for a pure force The Attempt at a Solution I...

Homework Statement During class, we were considering position dependent forces and we used the following differential equation to describe what is happening to the object in this case: m*(d2x/dt2) = F(x) (i.e. ma=F(x)) Then, we were introduced the potential V(x) which we defined as: F(x) =...

Why do conservative forces conserve mechanical energy while non conservative forces do not? According to me, What makes the conservative forces path independent is that for a particular case they always act in a fixed direction irrespective of the direction of motion of the object on which they...

hello :) my question is about a solved example in gregory's book first of all , assuming that that a cylinder with radius "a" is rolling without slipping towrad the y direction in an incline plane with angle θ with the horizon and the cylinder him self is rotating with angle Φ about him self...

A ship is being pulled by tugboats with forces of 300 N and 800 N. The angle between the forces is 45 degrees. My question is how can we find the angle between the force vectors and the x-axis? Would it just be 45/2 =22.5 degrees or would it be different because the forces have different...

I've lately began working with Newtons laws problems at school again, and I've already ran into a few problems. When making calculations and solving problems, it is often nessecary to understand when forces are equal to zero, and when they are not. Since every force has an equal and opposite...

Homework Statement Why we need to replace the 10kip load at 2ft from D to D ? Homework EquationsThe Attempt at a Solution IMO it's wrong ... There's no need to do that .

Homework Statement I couldn't get the forces in equlibrium in this question Homework EquationsThe Attempt at a Solution VA + VD = 35(3.5) + 10+15 = 147.5 sum of moment about D = -35(3.5)(1.75+ 3.7) +15(1) + VA(3.5 + 1.7+ 2) = 0 VA = 90.6upwards Sum of moment about C = -35(3.5)(1.75+1.7)...

What happens if I have a permanent magnet outside an ideal solenoid? Does the permanent magnet rotate until the system reaches an energy minimum in its magnetic fields? Or does the permanent magnet fail to rotate because the magnetic field of the solenoid does not reach the magnet? Wouldn't...

I have been reading many examples of control volume calculations regarding nozzles They all end up with a reaction force on the nozzle in the direction of the flow. I can't understand this from a Conservation of momentum perspective. I would expect that the reaction force, by Newtons third...

Homework Statement A pith ball is charged by contact with a Van De Graaff machine, and is repelled away from the dome. It remains at its location. Using the chart given, what is the mass of the pith ball? Distance between centre of generator and pith ball...

gluons can form glueballs, and glueballs can have spin-0 and spin-2 as a composite boson of spin-2, does it mediate new forces/interactions, and would a spin-2 glueball always be attractive the way gravitons are? do spin-0 glueballs form a condensate similar to the higgs field?

Homework Statement HELP! L-shaped tank problem! figure: http://www.webassign.net/hrw/hrw7_14-33.gif The L-shaped tank shown below is filled with water and is open at the top. (a) If d = 7.0 m, what is the force on face A due to the water? (b) What is the force on face B due to the water...

Homework Statement Two parallel wires have currents passed through them which are in the same direction. Draw a diagram showing the directions of the currents and of the forces on the wires. Alternating currents are now passed through the wires. Explain what forces would act if the currents...

Two questions I had: 1. How is the force of friction of the tires pointed inwards to cause centripetal acceleration? If the tire is rotated when trying to turn, the car is still traveling with a velocity perpendicular to the circle and force of friction would still be counteracting the...

Homework Statement An 8.5 gram slug is fired East from a 0.357 magnum hand gun held 1.5 meters above the ground. The muzzle velocity (as the projectile leaves the gun) is 1400 ft/sec. The bullet is accelerated at a constant rate as it travels through the 10 cm long barrel. After leaving the...

In relation to two objects with a gravitational field on them (i.e. a planet and its moon), would there be two pairs of partner forces (the force of gravity exerted from each object and the resulting partner force from each force of gravity)? For example with the Earth and moon: 1. Force of...

Homework Statement Homework EquationsThe Attempt at a Solution I'm having trouble coming up with the equations for the system. At first, I thought that m2 = m1sin(theta), but that's not correct. How can I set this problem up?

Homework Statement On a farm, you are pushing on a stubborn pig with a constant horizontal force with magnitude 34.1 N and direction 37.0∘counterclockwise from the +x-axis. a) How much work does this force do during a displacement of the pig that is s⃗ =(5.00m)ι^? b) How much work does this...

Homework Statement In this experiment, a suspended metre-ruler lies in a series of equilibrium under non-parallel forces. Homework Equations The apparatus consists of the following. A metre rule suspended by strings which make an angle with the vertical. The strings run over pulleys which are...

Homework Statement I have a man who is 100kg and a barrel of bricks weighing at 220kg. The man is using a pulley to lower the bricks onto the ground however since they are much higher in weight he rapidly travels up. Then the bricks fall onto the ground and the barrel weighs 60kg since it's...

Homework Statement At a construction site, a small crane is raising two boxes of nails on a plank to the roof. One box has already been opened and is half full, while the other box is new. The boxes, including the nails weigh 10kg and 20kg, respectively, and are the same size. If the...

If one fires a pistol while holding it in one's hand, the pistol will exert a backwards force above the grip of the hand, causing the gun to both move backwards as well as exerting a torque, as the hand is essentially behaving as a fulcrum. If a pistol is fired in a gravity-free environment with...

Homework Statement Two rods of the same material, of equal length l, and of cross section A and 2A respectively, are mounted between two rigid (i.e., nondeformable) cross frames. The frames are pulled by a pair of forces P, located at distance x from the thin bar. Derive an expression for the...

Homework Statement sam makes a punch hole with the perforater( two holes ). She presses the lever at A down with a force of 40 N. Calculate the total force which a single pin presses on the paper. Homework Equations http://s6.postimg.org/yx62wbild/image.png The Attempt at a Solution would it...

Homework Statement Can someone please help me with this A level physics question on Mechanics. Help will be appreciated. The picture of question is attached. :D Thank you Homework EquationsThe Attempt at a Solution [/B]sin20x590=201.79N or cos70x590=201.79N

Homework Statement A positive point charge Q_1 (4.0 µC) and a negative point charge Q_2 are placed near each other. When a negative charge Q is placed in the middle between the two point charges, the magnitude of the resultant forces on Q_1 and Q_2 doubles. What is the charge of Q? (answer...

So I've been given this practice problem for a test tomorrow and have no clue how to do it. Info: Students Perform a lab and record data on how changes in mass affect acceleration "Derive an equation that you graph to make a linear relationship from the recorded data." Given is a data table...

Homework Statement Hello, this problem is cracking my mind for days, and I haven't solved it yet :( Crane dimensions: See image Mass of the crane: 10Tons Mass center: G Maximum Load: 4Tons Counterweight: P Weight of the counterweight: ? "A" says: when you have a maximum load (4Tons) at the...

Homework Statement Determine the smallest force P that will cause the spool to have impending motion. Homework Equations Equations of equilibrium, and static frictional equations. ##ΣFx = 0;## ##ΣFy = 0;## ##ΣMb = 0;## ##Fsa = μNa## ##Fsb = μNb## The Attempt at a Solution My first...

Homework Statement [/B] Determine the moment about point B of each of the three forces acting on the beam. Homework Equations M = F*d⊥ The Attempt at a Solution I went and found the components for each of the forces. Please double check it if I did them right: F1 : Fx = 0 Fy = 375 lb F2: Fx...

Homework Statement the main question asks: "If the book is initially at rest, what is its speed after it has traveled 0.400 m up the wall?" Homework Equations ∑F = m*a vf2 = vi2 + 2 * a * d , when initial velocity is 0. The Attempt at a Solution So here's my free body diagram: and out of...

I'm very new to physics and am doing a crash higher course. I am currently tackling dynamics, and here is one of the questions I was given. 8 ) A car of mass 800kg is accelerated from rest to 18m/s in 12 seconds. a) What is the size of the resultant force acting on the car b) How far does it...

Consider a free-falling object with known mass and center of mass being acted upon by four forces -- force of gravity at the center of mass, as well as three additional force vectors applied at known positions on the body. Is it possible to calculate, in closed form, the position and...

Homework Statement Determine the magnitude of the resultant forces and direction of the resultant as measured clockwise from the positive x axis. Homework EquationsThe Attempt at a Solution Please help. I have entered my answers into masteringengineering.com and it keeps telling me my answers...

in broken supersymmetry every fermion has a super partner that is a boson, with same internal quantum numbers, except mass. i.e superpartner of an electron is a selectron, which is a boson. in QFT gauge bosons are force carriers. gauge bosons with mass create a force that is short-ranged...

Homework Statement Hello, I have attached a physics problem that I solved yet some answers (in red+the first answer) are wrong and I can't find out why... Homework Equations [/B]The Attempt at a Solution [/B]