What is Pull: Definition and 326 Discussions

I'm only an interested layman so please forgive my lack of knowledge but assuming the universe is flat, infinite and the cosmological principle holds then why wouldn't the attractive force between galaxies cancel out? If I think of a 2d analogy such as the surface of a sphere, and there were...

Homework Statement On December 25, 2004, the Huygens probe separated from the Cassini spacecraft orbiting Saturn and began a 22 day journey to Saturn's giant moon Titan (see the figure below (Figure 1) ), on whose surface it landed. It is useful to know that Titan is 1.22×106 km from the...

I was watching a show on one of the science channels a couple of nights ago and I think I heard that Jupiter's gravitational pull on the sun is around half a million miles (or could have been kilometers). Now, depending on Jupiter's position in relationship to Earths, at any time does it...

Consider a mass m with a prestressed pull spring on either end, each attached to a wall. Let k1 and k2 be the pull spring constants of the springs. A displacement of the mass by a distance x results in the first spring k1 lengthening by a distance x(and pulling in the - direction), while the...

I was thinking about the forces holding atoms together. Some materials seem very, very strong. But if we take thinner and thinner slices of any material it is easy to imagine that pretty soon no matter what material it is we'll have a slice so thin it would be difficult not to tear it. So...

Homework Statement The plug for the drain of a water tower is located 3.0 m below the surface. The plug is circular and has a diameter of 5.0 cm. If the density of water is 1000 kg/m3 , how much force is required to remove the plug (you may ignore the weight of the plug itself) Homework...

Homework Statement Based on a circuit diagram below Homework Equations None really The Attempt at a Solution So I was going through some past exams papers and encountered this question. However at the top it says it's a Pull-down circuit. Now I know that pull-down circuits utilize nmos...

I am trying estimate the approximate value in gauss of the magnetic field of a magnet I have based on its pull force, and I am wondering if anyone can comment on the validity of my method. I have tested the pull force of my magnet by weighing the heaviest object it can hold. I have also found...

Hi, I have this IC Datasheet: http://www.ti.com/lit/ds/schs015c/schs015c.pdf I need a pull down resistor at one of the input pins but I am not sure what value to use. How can I calculate what value resistor I need ?, can someone give me a specific range ?

Hi there, I am currently trying to work out what force I will need to pull the curtain out and in (in the system shown in the attached illustration) so that I can calculate the torque required to turn the black cylinder component and therefore find out what motor I will need. I am simply...

Homework Statement "A 68 kg crate is dragged across a floor by pulling on a rope attached to the crate and inclined 15° above the horizontal. (a) If the coefficient of static friction is 0.50, what minimum force magnitude is required from the rope to start the crate moving? (b) If μk = 0.35...

Homework Statement You are given a choice of two methods of pulling a 2 kg sled for a distance of 7 meters at a constant speed. If the coefficient of friction is 0.1, which method do you select as involving the least amount of pull on your part? Option 1 is a picture depicting the sled on a...

How does movement of the creator of gravity field( mass or energy density) affect the magnetude of exerted gravitational field ! Is there any relation at all ?

According to the sticky bead argument, gravitational waves do carry energy. As such, are they, like photons (EM waves), subject to the gravitational pull of planetary bodies?

In an experiment I hope to carry out, one of my "constants" are velocity (constant velocity). I must say a way I will keep this value constant. For example I can not say "I will try my best to pull mass at a constant velocity" "I will take a video of the experiment. When I examine the video, I...

Homework Statement A 7 kg block on a flat surface moves from 2 m/s to 4 m/s over 5 m. The coefficient of friction between the block and the surface is 1. How much force was used to move the block? Homework Equations Honestly, my physics instructor gave us so many worksheets with so many...

Homework Statement A large sphere exists in space, which has a mass of 1 * 10^28 kg The sphere has a radius of 100,000 km What will be its gravitational pull (aka: "relative gravity") on its surface in terms of gs (1 "g" being equal to the gravitational pull of the Earth which is 9.807 m/s^2)...

Hi, I'll start by saying I'm new here. I'm in my first year at college and I want to be an inventor. My question is this - if there was an airplane propeller that could pull on air instead of pushing against it to create thrust, would it be more effective at 1. creating thrust and 2. avoiding...

Hi, I am investigating the possibility of using 2 oppositely polarised electromagnetics to locate 2 moving bodies into the correct position as they move towards each other and would appreciate some thoughts on the feasibility of the solution and ways it might be improved. I am proposing using...

I know once the escape velocity is reached, the object will continuous to move away from the Earth. But the Earth's gravity can still act on the object no matter how far it goes, so what keeps the object from stopping or even returning back to Earth? Thanks in advance!

Hi everyone, I am looking for any available experimental data which models off-road vehicle travel in clay and measures tyre and soil parameters. Parameters I am looking for include pull, torque, shear strength of the soil, sinkage, slip and deflection. If anyone knows of any available raw data...

So last year, I was told by a friend that no Acceleration means no Force, Mathematically, this makes sense (500 Kg * 0 m/s^2 = 0 N), but intuitively, I can't wrap my head around it. Maybe this is because of language and the way we use the word force in normal conversation, but in physics it is...

Hi... any idea on how to calculate force needed to pull up something stuck on the ground? ex: Boot stuck on mud person sinking on quicksand or car sinking in water

Hello, I am working on selection of motor for intermittent wrapping steel strip on a reel, intermittent because system is equipped with a sensor which triggers motor after the strip reaches a certain level in the buffer box and then motor stops when the level of strip falls below another fixed...

i was wondering, instead of thinking the apple was pulled down by some force to Earth , why didn't he think that there was a force pushed the apple down from above? , imagine when you leave in that particular year when he was alive.

If even feasible, what minimum type/size cable reqd with trolly attached that would have maximum 1000 lb load suspended from it, that would be pulled up, from atop, by second separate free line for the following location; 1,000 foot elevation change to where base anchor point was, horizontally...

Hey guys, I am planning to do a project which can pull 2 persons through water at some speed. For example a casualty and a lifeguard This would be similar to a sea scooter which divers use, however it floats on the water only it does not dive. I am not sure whether to post it here or in the...

When a ball falls towards Earth, what is actually happenning... Is the Earth PULLING the ball? or Is the space PUSHING the ball? (Be assured that I can understand you. Before becoming a teacher of literature, I studied Physics, Chemistry and Mathematics upto graduation level. The previous...

Heya, I am new to this forum and want to start with a tricky question... There is a cylindrical neodymium magnet, d = 40mm, height = 5 mm, hole in the middle (also round shaped cylindrical) d = 10mm. There is also a pure iron ball d = 12mm. The ball is set on a non-magnetic stand at 500 meters...

Hello I am a mechanical engineer who is teaching himself the math of exterior algebra and differential forms. It is not easy for me and I have had many SIMPLE stumbling blocks due to my not respecting algebra. May I ask for help on some simple aspects? (Please be patient with me.) My...

How concerned should I be when the latest update for Adobe Flash Player includes the following paragraph? "7. Connectivity and Privacy. You acknowledge and agree to the following: 7.1 Use of PDF Files. When you Use the Software to open a PDF file that has been enabled to display ads, your...

Homework Statement For the equation ∇ x E = -∂B/∂t I took the curl of both sides to get ∇ x (∇ x E) = ∇ x -∂B/∂t I feel like it'd be very wrong to pull out the time derivative. Am I correct?

Everything that has mass , posseses gravitational pull. We as humans do have mass, and thus posses gravitational pull too ? If so , do we posses tiny amount of gravitational pull ?

Hi all, I am an electrical engineer and feel I should know this (embarrassing!), but I for the life of me still can't quite get this concept. I understand conceptually the idea behind a pull up or a pull down, in that we want the IC to read a high state, by defaultm in the case of a pull up...

Hi Guys, I am going to restart the discussion in the following thread https://www.physicsforums.com/threads/calculate-pull-force-of-magnet.162157/ I working on similar system where i am interesting to calculate the pull force of permanent magnet on nanoparticles in water suspension. I am not...

I am trying to figure out how to calculate the force it takes to pull a chin strap from a helmet. Is there a special scale that you can use? I am not in school anymore and it has been years since I have done any math or science, so small words are greatly appreciated.

http://faculty.mint.ua.edu/~pleclair/ph125/Misc/exam2_form_a_solns.pdf On page 1, problem 1, where it shows a mass M and another mass 3M connected by a cord and spring. Then the cord is burned off, and then the spring "pushes the blocks away" I get the momentum conservation and how to work the...

Can pull up exercise (at a younger age, say, before 15 years old) increase height? My guess is yes, since weight lifting could decrease height (Or that is another myth?) If yes, by how much?

for example say I were to roll a magnetic ball down a hill and placed another magnet at the end of the hill, would the magnetic ball hit the magnet with more force than a non magnetic ball. This question is for my science fair, all people answering must be prepared to answer follow-up questions...

Homework Statement Problem 3.12 from Kleppner & Kolenkow A ski tow consists of a long belt of rope around two pulleys, one at the bottom of a slope and the other at the top. The pulleys are driven by a husky electric motor so that the rope moves at a steady speed of 1.5 m/s. The pulleys are...

Homework Statement A uniform rope of length L and mass M is held on a frictionless table by a force F. One fourth of its length (¼L) is hanging over the edge. Find the work required to pull the hanging part back onto the table. Homework Equations W=Fd The Attempt at a Solution I have no...

Is this established or is it dependent on the size of the black hole? http://www.space.com/22180-neutron-stars.html Neutron stars pack their mass inside a 20-kilometer (12.4 miles) diameter. They are so dense that a single teaspoon would weigh a billion tons — assuming you somehow managed to...

Homework Statement You are lowering two boxes, one on top of the other, down the ramp shown in the figure by pulling on a rope parallel to the surface of the ramp. Both boxes move together at a constant speed of 19.0cm/s . The coefficient of kinetic friction between the ramp and the lower box...

Hi there, to answer some people believing in astrology, I wanted to know what was the order of magnitude of the difference of the gravitational pull between famous stars & the man-made satellites... I have no knowledge in math or so I have no idea... I just thought that I would find it...

say you fell beyond the event horizon of a black hole can another black hole passing close enough pull you out?

when you approach it from different directions?

Homework Statement A 2 m long chain of mass 4 kg rests on a table such that 60 cm of it hangs vertically downwards from the table. If the chain has uniform mass distribution, calculate the work done in pulling the entire chain upwards. Ignore the frictional force. Homework Equations...

Hi, Can somebody give me the formula for pull force of ring magnet(permanent. not solenoid or electric) on a metal rod. Also is the formula for pull force by a solenoid given below correct. If not let me know the correct one for the below. Force = ((N x I)^2 x μ x A) / (2 x g^2) N =...

Hello. What would happen if there's a mistake in the pull up circuit where nMOSFET is used in the pull up circuit while the pMOSFET is used in the pull down circuit? What would happen to the action of the inverter, output voltage range and characteristics? I have been trying to find some clues...

Hello. What would happen if there's a mistake in the pull up circuit where nMOSFET is used in the pull up circuit while the pMOSFET is used in the pull down circuit? What would happen to the action of the inverter, output voltage range and characteristics? I have been trying to find some...