Newton Definition and 525 Threads

  1. R

    B Can someone please explain this paragraph from A Brief History Of Time

    what does it mean when you say the stars all fall in on each other?And what does the line uniform distribution of stars outside this region mean?and what does this line mean- again fall in?what does fall in mean? would really appreciate some help in understanding the meaning in simpler words...
  2. F

    Uncovering the Origins of F = ma: Newton's Experiment and Measurements

    Hi, I am concluding a phD in Nanotechnology and I just started studying physics by myself. I just wonder how did Newton obtain F = ma? What experiment did he perform? Which 2 variables did he measure? How did he measure them?
  3. Samwell

    How long will it take for an object to stop with a defined force over time?

    Hello, I have the force defined as a function of time, where F=A-Bt and A=100N, B=100Ns-1. I have to determine, how long it will take for object to stop, if t0=0s and v0=0,2ms-1 and mass of the object is m=10kg. Can somebody please help me with this, because I'm having hard time with this task.
  4. G

    Understanding forced motion in space

    Hello, Can you please explain the analogy oft quoted to explain the concept of applied motion to objects in space, which goes as follows : 1. You are standing on a skateboard or sitting in a boat floating on the water, holding a bowling ball. 2. You throw the bowling ball towards the back of...
  5. Quentin_Phys

    Relationship between the Volume of a balloon and the time it takes to deflate

    I would like to ask a question on whether there is a proportionality between volume of a balloon, and the time it takes to deflate. I have conducted several balloon hovercraft experiments. I need to find the relationship between the amount of air pumped into the balloon and how long the...
  6. T

    Is 1800 Newton meters enough torque to generate 1.5 kilowatts of power?

    i am working on new project so i could use your help. Please and Thank you Tony
  7. taalf

    Formula for fictitious moments

    Hi All, Everyone knows so called "fictitious" forces, also known as "inertial" forces. They are forces felt by some mass point placed in a non-inertial frame. For example: a ball in a moving car or in a carousel. Maybe most intuitive fictitious forces are centrifugal forces, but there are also...
  8. pixel

    I Bending of light - Newton vs. Einstein

    Using Newton's equation for gravity and assuming a corpuscular theory of light, one can calculate the angle that light would bend in a gravitational field. General relativity predicts a bend that is twice as large. In the Newtonian limit of GR (which includes weak gravity), does the GR...
  9. Psyrus

    Grams vs. Newtons: Why Do I See Weights Measured in Grams?

    Ok so I've asked my physics teacher and a statics teacher as well and I couldn't get a straight answer from either. So here's my questions... Correct me if I'm wrong, but isn't the gram a unit of mass? Not weight? I thought that for mass to become a unit of weight, it has to have to...
  10. T

    What is the Mathematical Definition of an Inertial Frame?

    This question concerns inertial frames. I am aware that an inertial frame is one that is not accelerating. I am aware of an alternative definition: it is one on which no forces are applied. (Yes, they are the same thing.) I am also aware of the d'Alembert "forces" that appear when a frame is...
  11. Srihari05

    I How Does Feynman's Theory Explain Light Reflection in Glass?

    I recently started reading Feynmans book QED. There are a couple of questions I have regarding his theory on the percentage of light that is reflected of two surfaces of glass. My question is as follows, A piece of glass in fact has four surfaces. The front of the glass the back side of...
  12. W

    I Is quantum mechanics formulated from 1st principles?

    I was surprised recently to learn that one of the reasons both Newton and Einstein were so revolutionary was that they performed a neat mathematical trick. For Newton, it was the mathematical derivation of Kepler's laws from Newton's laws of gravitation and motion. For Einstein, it was the...
  13. L

    MHB Solving Equations Using Bisection, Newton, and Secant Methods

    Task Use the Bisection, Newton, and Secant methods to solve (to at least 8 signicant figures) the equation sin(x) = 0.98 cos(2x2) over the interval [0, 2.5], in radiant units. For the Newton method, try with several different initial guesses including x0 = 1. With the Secant method, use the same...
  14. C

    F=ma -- How did Newton find this?

    I did some googling but only found nothing to answer my question. How did Newton come up with this formula, literally/physically? Did he have chunks of stuff and moved them around, then logged various results. Then maybe he played around with various formulas and saw which fit the data?
  15. JTC

    Contributions to Dynamics - China

    Hello, To ensconce this question properly, we know that some of the major contributions to the discipline of rigid body and classical particle dynamics came from: Newton, Euler, Hamilton, Lagrange and so on... (no need to suggest other western names right now - I am aware of them). However I...
  16. D

    Effect of ambient pressure on Newton cooling (water)

    If I have a laboratory water bath (circulated for homogeneity in temp) that I will monitor over a period of time (probably 2 scenarios, an hour at most, and then at least 24 hours or longer), how do I quantify the effect of atmospheric pressure in our test lab. What I will do is use an...
  17. M

    Solving the Einstein Gravity Tensor for the Newton Potential

    Homework Statement The Lagrangian density for the ##h=h^{00}## term of the Einstein gravity tensor can be simplified to: $$L=-\frac{1}{2}h\Box h + (M_p)^ah^2\Box h - (M_p)^b h T$$ The equations of motion following from this Lagrangian looks roughly like (I didn't calculate this, they are given...
  18. S

    Experiment on Newtons First Law

    I am wondering if anyone knows of a good resource to see Newtons first law in action. For example, a block being pulled by increasing force until it moves?
  19. F

    Solve Tension in Rope: 110 Kg Anvil & 9.81m/s^2 Force

    Homework Statement I have a rope held by a hook, which is attached to the ceiling by a chain (with an angle theta), in one side, the rope (with an angle alpha) is attached to a a wall, in the other side, the rope is carrying an anvil of 110 Kg mass in vertical position. What is the tension in...
  20. Yan_Dalton

    I Why do objects with mass attract each other?

    In most cases, we know why things happen. Protons can stick with each other because of the strong nuclear force. There's all kinds of forces and we know mostly about why they occur and how they are transmitted. But I don't understand gravity. Why do objects with mass attract each other ? I know...
  21. Z

    Help with Newton root approximation proof

    Homework Statement Suppose we have: ## f(x) = x^2 - b ## ## b > 0 ## ## x_0 = b ## And a sequence is defined by: ## x_{i+1} = x_i - \frac{f(x_i)}{f'(x_i) } ## prove ## \forall i \in N ( x_i > 0 ) ## Homework Equations The Attempt at a Solution a)Here I tried solving for ## x_1 ## as...
  22. D

    Measuring the Force Required to Separate Two Magnets at a Distance

    Hi, i have a question. I need to know how much Newton it takes to separate 2 magnets or a magnet from a from a piece of metal. I've bought a spring scale that measures max 50 gram, so very accurate. Now what if i attach the scale to the magnet and i pull it horizontally just enough to...
  23. C

    How is Weight Distributed on a Man's Feet on a Turning Railroad Car?

    Homework Statement The problem relates to the subject of torque and angular momentum: A man of mass ## M ## stands on a railroad car that is rounding an unbanked turn of radius R at speed v. His center of mass is height ## L ## above the car, and his feet are distance ## d ## apart. The man is...
  24. thebosonbreaker

    B Is the lift generated by a hummingbird's wings an example of Newton's Third Law?

    Hello, I understand that Newton's laws of motion can explain how a hummingbird is able to hover in front of flowers. There is one question I have in particular, which is, Is the lift generated by the wings of the bird and its weight force an example of a pair of Newton's third law forces? They...
  25. F

    A Two-Body-Problem with Changing Mass

    Hi, I would like to ask you what happens when you change (gradually) a mass of one body in a classical two-body-problem. May it lead to such results? Many thanks. Flor
  26. M

    Can G force be converted to Newton?

    I'm sizing a shock absorber at the moment for a project and I have accelerometer readings of a road going over bumps (3 gs). I have already applied gravity to the load to get my 5.5kN If the weight of the static load at that point is 5.5kN would it be safe to say the spring needs to be sized to...
  27. thebosonbreaker

    Why were Newton's laws of motion discovered so late?

    Hi, I had a thought recently which gave rise to a rather interesting query. A helicopter works and is able to fly due to Newton's third law of motion. The propellers rotate at a high speed and exert a force on the air beneath them. By N3L, the air therefore exerts an upwards force on the...
  28. Pranav

    B F=ma -- True or an Illusion....

    Imagine, There's a ball in deep space traveling with a constant velocity of 25m/s and is having mass 25kg. Now as I said, ball is traveling with a constant velocity that simply means acceleration=0 and now if we calculate the force with F=ma we will end up with 0. But if that ball collide with a...
  29. A

    Newton's Rings and Thin Film Interference

    Homework Statement A total of 31 bright and 31 dark Newton's rings (not counting the dark spot at the center) are observed when 550-nm light falls normally on a planoconvex lens resting on a flat glass surface. How much thicker is the center than the edges? Homework Equations 2t = mλ 2t =...
  30. M

    Shape of water in a rotating container along A vertical axis

    Hi! I am currently working on a project that includes rotating a water-filled container. The container is NOT spinning about its vertical axis, but about the vertical axis of the rotating disc. I am aware that the surface shape of water in a rotating bucket takes the shape of a parabola when it...
  31. V

    Understanding Newton's Laws: The Confusion Between II and III Revealed

    I am not a teacher, but I have made an interesting observation regarding classical mechanics education. It is surprisingly common that even students at academic level do not seem to fully understand Newton's third law (action and reaction) and confuse it with Newton's second law...
  32. J

    Particle moving down a cone (Newtonian formulation)

    Hi, This a Classical Mechanics problem I've been trying to solve for a few days now. I cannot use Lagrangian or Hamiltonian formulation, it must be solved using classical Newtonian formulation. One must determine the equations of movement of the particle in cartesian, spherical and cylindrical...
  33. L

    Kinetic Energy and Newton Forces - distance/speed

    Homework Statement A sled of mass m is given a kick on a frozen pond. The kick imparts to it an initial speed of 2.20 m/s. The coefficient of kinetic friction between sled and ice is 0.150. Use energy considerations to find the distance the sled moves before it stops Homework Equations...
  34. L

    Pulley at an Angle Problem - Newton Forces

    Homework Statement Homework Equations Friction Force = normal force * static coefficient for friction Fnet = ma The Attempt at a Solution So i drew the free-body diagrams for both the objects...[/B] Im trying to figure out the tension in the 2nd free body diagram and i know that it's...
  35. B

    Newton's Law: Mass at Rest vs Falling from 100m

    Experts tell me that: "At average gravity on Earth (conventionally, g = 9.80665 m/s2), a kilogram mass exerts a force of about 9.8 Newtons. An average-sized apple exerts about one Newton of force, which we measure as the apple's weight.. After one second, you're falling 9.8 m/s.. .. falling from...
  36. L

    Two Questions on Newton Law Problems

    These are conceptual questions, and i just want to really understand why the answer is the answer! 1. Homework Statement 1) A force acts to push two boxes, box 1 and box 2, across a floor (assume for this problem that friction is negligible). The two boxes are stacked such that the force...
  37. Sophrosyne

    Scientific law vs. theory, Newton vs. Einstein

    My son is taking a chemistry class in high school, and he was telling me this morning that their teacher had taught them there was some kind of fundamental distinction between scientific laws and theories. He said the teacher had told them that laws are just fundamental regularities observed in...
  38. J

    Torque and force on a tire iron

    So I was curious about something. Having a flat tire today and having to change my tire made me wonder. I understand torque and force are 2 different things though related they have separate meanings. So my question is if I have a 2 foot tire iron and I am torquing my nuts. Let's say they...
  39. K

    B Relation between sum of the forces and energy

    In the picture above, there are three balls in separated small elevators. Elevator A lifts the ball upwards, elevator B stays still, elevator C moves the ball downwards, all in constant speed. (And this is a model, a simplification of the reality, we assume no other forces on the balls other...
  40. J

    What if the actual force for a Newton was different?

    ince f=ma, and we derive whatever the force it takes to accelerate a specific mass at a specific acceleration as a unit of force. I understand this ratio of actual force will always be the same in the entire universe but is there a reason why for example 1kg accelerated a 1m/s^2=1 N which is...
  41. B

    Hydrualic pressure moving plug in pipe

    Homework Statement A plug with a given mass is placed in the end of a horizontal pipe to hold water at a given pressure behind it. Is there any way to calculate how far this plug would move in the x-axis if it suddenly lost it's grip against the pipe wall, and it was situated a given height...
  42. J

    Why is a Newton of force .225 pounds?

    General physics question regarding force and gravity. Hypothetically speaking if every piece of mass weighed double. If something that weighed 1 Pound is now 2 pounds. If you weigh 100 pounds now you weigh 200 pounds . Assume gravity is still 9.8ms/sq. and you never experience gravity any...
  43. JTC

    Newton's Principia and Euclid's Elements

    I have always wanted to read the textbooks in the thread title. But their styld is so old. Does someone know of any "middle of the road" textbooks? By that, I mean: books that basically teach what these two men wrote, but, perhaps with updated language, or some really-not-essential stuff...
  44. T

    Center of Mass Velocity in Multiple Dimmensions

    I was doing some practice problems to become more familiar with the Center of Mass Velocity and I came across this one from (Noted in the picture) Engineering at Illinois, that relates the velocity of the center of mass in both the x and y direction, however I don't quit understand the answer...
  45. C

    What is so "genius" about the work of genius scientists?

    Many scientists are regarded as geniuses based on their work (Einstein, Newton, etc). What is it about their work that is so clever that few others could have done it?
  46. MikeGomez

    I Did Newton Believe in Absolute Motion? A Closer Look at His Arguments

    An interesting subject that was getting off topic from another thread… https://www.physicsforums.com/threads/does-gravitational-time-dilation-imply-spacetime-curvature.919181/ Note: Newton was not alone in this. Rene Descartes stated that the problem with relative motion is that every particle...
  47. N

    Newtons and Newton meters for pushing a weight

    Hi. I’m trying to build something and having very little basic physics am having to try and learn as I go along. Today I spoke to a company that makes damping units and I was asked how much force in Newton meters would be applied to the unit at the top speed. It’s a small cart weighing 70Kg and...
  48. I

    I What did Newton mean by "Ghosts of Departed Quantities"

    "Ghosts of Departed Quantities" And a host of ones own deity?
  49. P

    Is true force just "accepted" if it satisfies Newton law?

    So I understand the relationship between mass x acceleration=force but all that relationship tells me is "Whatever the force is to accelerate a given mass at a specific unit of acceleration = units of force, and we just accept whatever the unit of force is. example 1/ms² x 1 kg mass = 1 N...
  50. Quantum Velocity

    How did Newton explain his laws of motion?

    Hey guy! I used google but it didn't help so can you guy pleas tell me how Mr.Newton explained his law please. Thank!
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