Weight Definition and 1000 Threads

  1. T

    Engineering Problem using Pulleys with Weight in Equilibrium

    Dear all, I have the following problem: I need to find the compression "C" in the mast and the angle that the masts makes with the horizontal (X degrees). I know that the tension in the ropes "T" are of the same magnitude on both sides of the pulley, but I am struggling with finding C and X...
  2. S

    B 4 pounds over the weight limit of a tv stand

    I wanted to put a 39-pound tv on this tv stand: https://www.ikea.com/us/en/p/lack-tv-unit-black-brown-00566060/ The weight limit of top shelf is 35 pounds, but my tv weighs at 39 pounds. Is there any way I can adjust the force distribution so the shelf can hold my tv? tv has 2 base legs about...
  3. grade11studentgoaat

    Finding the direction of forces

    Tension force = 10lb[W] where do i put tension arrow in the full body diagram
  4. Manish_529

    Tension in a rope hanging between 2 trees

    I know that I can draw an FBD and apply Newton's 2nd law to find the relevant equations. But my question here is why is the mg vector or the weight of the entire rope same at every point on it I mean to say that if the mass of the entire rope is say M then how can a small point on the rope also...
  5. I_Try_Math

    Determining angular velocity of weight attached to a cord and cylinder

    ## a_t = r\alpha ## ## 9.8 \: m/s^2 = (.25 \: m)\alpha ## ## \alpha = 39.2 \: rad/s^2 ## Since the cylinder rotates through 20.01 radians after 5 m of cord has been removed: ## \omega_f^2 = \omega_0^2 + 2\alpha(\Delta\theta) ## ## \omega_f^2 = 2(39.2 \: rad/s^2)(20.01 \: rad) ## ## \omega_f...
  6. S

    I How to calculate the "weight" of this piece of metal?

    Hello, I would like to calculate the "weight" of a piece of metal. It seems a little confusing that weight is measured in Newtons or force. So I'm looking for a little help in understanding. if I consider a piece of average aluminum. Dimensions: Length: 60.96 mm Height: 60.96 mm Thickness...
  7. Quantum55151

    How Do Mass and Weight Differ?

    In the 2nd question, I definitely think it's D, because the force the rock exerts on your toe is equal in magnitude to the normal force the toe exerts on the rock which in turn is equal to the rock's weight, which is related to m by the constant g. In the 1st question, I am not as certain, but I...
  8. K

    Engineering and pressure related questions

    How did you find PF?: Friend I need to move a 2000 pound weight up twenty feet into the air on top of an eight inch diameter piston (surface area of 50 square inches) how much steady pressure would i need to achieve this and overcome the friction on the piston itself. Im trying to lift a door/wall
  9. A

    B Why Is an Object's Weight Equal to the Force of Gravity It Experiences?

    A relatively simple question has been bothering me for some time: Why is the weight of an object (the force the object exerts on a surface/rope) equal to the force of gravity that the body experiences in Earth’s gravitational field? Earth’s gravitational field accelerates all bodies in its...
  10. Ranku

    I Cavendish balance and mass of objects

    The Cavendish balance measures the gravitational constant G. To do so requires us to know the magnitude of the smaller and larger masses in the apparatus. However, mass is derived from the weight of an object, which is the gravitational force upon an object, which in turn requires the value of...
  11. Lotto

    B What forces act on a bar when you do pull-ups?

    I am not sure here, even though it is probably simple. If you just hang on the bar and don't move up, you act on the bar with a force equal to your weight. But when you want to do a pull-up, I would intuitively say that you act on the bar with a higher force. But when I think about it I would...
  12. T

    B How Does Inclined Load Affect Weight Distribution When Moving a Cabinet?

    Hello. I want to ask for advice. I know I probably won't understand it anyway, but maybe some information will help me. I did not find a solution to this problem on the Internet, which in itself I do not understand. We moved the cabinet and I can't calculate how much the weight on the opposite...
  13. DaveC426913

    B TV Series: 3 Body Problem - affects gravitational force?

    SPOILERS This obviously wouldn't happen to that extent, not without tearing the planet to pieces as well. But might they feel a reduction in weight at all? Obviously it's a pretty hypothetical question without any specifics about the distances to the suns but in theory at least.
  14. orazon

    How Does a Pulley System Affect Scale Readings?

    A kid is standing on a scale and holding a rope that goes through a pulley, on the other side the rope is connected to a spring and then to a 50N mass item. Assume that the kid's weight is 700N 1. While in static mode - what will the scale show? 2. The kid is now pulling the rope to get the mass...
  15. M

    I Experiment on the variation of weight with temperature

    Hello ! According to what I have read on the internet, the weight of a body varies with temperature, its mass remaining unchanged according to the theory of relativity. My question is what experiment is done to corroborate that the weight of a body increases with the increase in its...
  16. F

    Energy consumed by weight of gear on a multiday hike

    I'm trying to figure out how many extra kcal I would burn on a 600km hike with a 30,000m (30km) positive gain for every additional 100g (or 1kg, whatever) of gear in my backpack. It would obviously be a quite rough approximation, as there are significant variables such as the efficiency of a...
  17. J

    I What is the Uncertainty in the Total Weight of a Collection of Similar Items?

    Not a homework assignment. Just what must be a solved problem that I'm embarrassed I don't know how look up or figure out on my own. I want to know the total weight of a collection of N items. They are all similar but of different, unknown weights. My scale has a known accuracy of ±U units. If...
  18. biomajor

    Would one be pushing as much as their weight?

    Because one is effectively pushing in the same way as a chest press machine, wouldn't the work done be the same?
  19. T

    Frequency & Wavelength of a Vibrating Wire

    Good morning, I'm working through the problem from the homework statement above and answered it correctly, but I can't help but feel that something important is missing. I was able to correctly identify the sum of torques by using the following diagram, where the CCW rotational direction...
  20. Ineedhelpwithphysics

    Inclined Plane Vector Problem: Understanding the Use of Trigonometric Functions

    I'm not really asking for a solution for this problem I just want to clear up a confusion I have. Why are they multiplying the weight by the sin and cosine of the 30-degree angle? Isn't weight not affected by anything since it's constant? Also is the angle of friction 0 because it's a...
  21. bobbeh

    How to Analyze the FBD of a Toy Car on the Underside of a Dome?

    weight pointing down Fn pointing down and to the left (to the center of the dome) Fs pointing ..?? Should it not be off the page? Maybe up and off the page to oppose movement + gravity?
  22. L

    How Camera Jibs Remain at Any Angle Without Moving Counterbalances

    Hi, I am trying to understand how camera jibs work. They seem to be able to remain at whatever angle despite being balanced. The counter weight is static and does not move, yet the jib does not remain level nor does lift or drops. I have spoken to the operators and they mention they don't use...
  23. LCSphysicist

    Proving that e^{ikx} is primary with weight (h=\hbar = \alpha k^2/4)

    Where ##:## really means normal ordered, in the sense that ##:A(w)B(z): = \lim_{w \to z} \left ( A(w)B(z) - \langle A(w)B(z) \rangle \right )## ##\partial X(z) = \frac{\partial X(z)}{\partial z}## How do we go form the first line to the second one?? I am not understanding it! it seems to me...
  24. Frankenstein19

    Using 18% by weight ammonium hydroxide to make 16ppm aqueous solution

    TL;DR Summary: Used M1V1=M2V2 but am unsure if formula applies I feel like I could use M1V1=M2V2 but the 18% by weight ammonium hydroxide is confusing me so much. Density of ammonium hydroxide 18% is 0.926 g/cm3 18%V1=16mg/L*200L (18mg ammonium/100 mg of total solution) * V1 = 3,200mg...
  25. abdulbadii

    The ideal weight or force to push a drill

    What is and how is the estimation of the ideal weight or force to push (bit being in) a driller down when drilling (stainless) steel to bore 3-9 mm hole?
  26. D

    Construction Steel cage weight load capacity needed

    I have a VERTICAL standing square tube 1.25" x 1.25" x 1/16" thick. Length/Height = 79" Material = steel How do you determine its max load capacity for this tube when mounted vertically? I plan to use 18 of these vertical posts, evenly spaced, creating an 83" x 131" rectangular structure. They...
  27. haha0p1

    Finding the weight of an object submerged in water

    I have solved the question in the following way: The downward force is equal to the upward force. the upward force is equal to the weight of water displaced. If we find the weight of the water displaced then we will know the upward force. And since upward force is equal to downward force, we...
  28. S

    Calculating Weight Ratio of PEO and LiClO4 in PEO-LiClO4-Al2O3 PE Samples

    So i found this on a journal, and im wondering what is n and how can i calculate the weight percentage ratio between the PEO and LiClO4. Here is the instruction. To prepare PEO-LiClO4-Al2O3 PE samples, predetermined amounts of LiClO4 (such that oxygen to lithium ion ratio is n:1) and Al2O3 (as...
  29. J

    Does induced drag theory include the Lift = Weight condition?

    This is usual induced drag diagram. I have 2 questions: From Kutta–Joukowski theorem Fr is always perpendicular to effective airflow. 1. Does it mean for case without effective airflow(zero induced downward velocity), Fr is perpendicular to freestream airflow,so drag is zero? When effective...
  30. L

    I Bicycle front tire wobble due to weight on the back of the bike

    I am a bit overwhelmed with your forum site. I was not sure where to post my question...Here goes- Full details…I have an e-bike. It weighs about 55 pounds. I have ridden it for the last year with a canvas bag attached to the rear flat book carrier. The canvas bag measures 19” long, 9” tall and...
  31. Leo Liu

    Why doesn't aircraft weight affect descent angle in a gliding flight

    It's a homework question, but I feel like it fits better in this forum. The solution fails to convince me because C_D and C_L can be both written in terms of weight: $$C_L=\frac{2W}{\rho v^2 S}$$ $$C_D=C_{D0}+k_1 C_L(W)+K_2 C_L(W)^2$$ Question: Solution: Any insight will be appreciated.
  32. J

    I Does Pulse and Glide only work with manual transmissions and a kill switch?

    When car drive uphill, gravity/weight has drag component, that is reason why you must add more throttle compare to ligther car at same constant speed uphill. So logicaly car increase fuel consumption. But if you drive downhill, gravity/weight has thrust component, so your top speed("terminal...
  33. P

    Minimum screw thread engagement to support weight?

    Hello All, I know there are rules of thumb and thread engagement calculators online but I am trying to find mathematically what the minimum number of threads acceptable would be. I currently have an eyebolt that will be torqued to a specific value. This eyebolt setup will then need to lift a...
  34. Z

    Forces on a rope when catching a free falling weight

    If I am not wrong, F = 2*10*9.81*4/0.2 = 3924N (0.2m considering 5% stretch in 4m long rope)
  35. S

    How can mass be measured independently of gravity?

    Hello The formula Mgh is commonly accepted as the work done by raising a mass by a distance h, where M is defined as the mass of the object raised. However, is this really the mass, or the weight, simply obtained by weighing the object? If it's the weight, then doesn't the equation...
  36. S

    Apparent weight problem (kinematics + conservation of Energy + Newton's laws)

    Hello there, I have tried the problem but don't get a different of 6g's as I am supposed to. I am not sure whether I interpreted the problem in the correct way, but I would love some feedback/hints on what went wrong in my solution, thanks in advance. Solution: SITUATION DRAWINGS + FBDS so...
  37. B

    I Shock Load on Rope: Weight Limit Analysis

    Hello, I’m not sure if the proper term is shock load. If a person is using a device and rope to lower themselves from a high point and they’re descending fast and then suddenly stop does that create a shock load? The device attaches to the rope and when a person squeezes the device it allows...
  38. M

    I Weight required to hang straight down with known torque

    How much Weight (W) is required to keep a weight hanging straight down when the torque is known on a rotating shaft? Please see attached image. Assume a lever weight of zero to keep it simple.
  39. M

    I Effective weight vs distance to the point of attachment of the weight

    Hi, I want to know how to calculate the effective weight if i have an object with the weight 'X' that is mounted from the side to a wall, and what happens with the weight if i increase the distance between the wall and the object. The reason i ask is as follows for the interested. I have a...
  40. T

    Knowing when to decompose weight vector vs. normal vector

    Good afternoon everyone, I have a question on Newton's 2nd Law regarding objects on a generic incline. Take for example, a car on a banked curve: Here in the picture I've provided, you can see that the normal force has been decomposed into the x and y components via sine and cosine of the...
  41. C

    I Calculating your weight in an elevator

    I was watching one of Walter Lewin's lectures, he gave an example of a scale placed at your feet in a moving platform, apparently your weight changes when the moving platform accelerates downward, my question is if my reasoning is correct. I'm wondering why your feet stay in contact with the...
  42. D

    Home project: Kilogram Force on wheel bearings

    Hi all. I'm designing a custom spare wheel carrier for my 4wd and currently seeking knowledge on which bearings to use, so I need to work out what force on the bearings will be when it's open (closed will be locked and fully supported!) The example image is simplified for calculation. Close...
  43. D

    How Can I Maximize My Learning Potential as a New Scientist?

    Hi everyone! New member here, not much smarter than a monkey but willing to learn. Thanks for the opportunity to learn from yas!
  44. J

    I Apparent Weight problem (falling beam)

    Each weight: 2 Kg Hello All, I'm trying to understand an "apparent weight" problem and check my answer. Please use the picture attached. A weightless beam is at first resting over my palm, it has one 2 kg weight on each end of it. It is suspended to the ceiling by a rubber band. I drop it and...
  45. D

    Will my fish tank stand hold the weight?

    Tank volume is 768l plus the tank and rock to go inside 2000m x 640mm wide x 600mm high Stand is made of 35mm square x 3mm wall thickness. Tank width is the same as the steel frame, notice the tank is not over the end legs. Wooden top is 50mm thick pined and glued planks... 4x top supports...
  46. B

    B What is my apparent weight in water?

    Hi, I was wondering, what is my apparent weight in water? For example, when I tiptoe on land, my calf muscles are pretty much lifting all my body weight. But if I were to tiptoe with just my head out of the water, how much weight would my calves be lifting? And as I move to shallower water, how...
  47. L

    Pulley system to balance the weight of a person

    Since we are dealing with an ideal rope, we have that ##T_1=T_2=T_3=F and T_2+T_3=2F=(m+m_p)g\Leftrightarrow F=\frac{m+m_p}{2}g.## ##T_4=3F+(m+m_p+M_p)g=\frac{3}{2}(m+m_p)g+(m+m_p+M_p)g=(\frac{5}{2}m+\frac{5}{2}m_p+M_p)g## and ##T_5=mg-2F.## Is this correct? If not, I woould appreciate a brief...
  48. rudransh verma

    B Understanding Weight and Inertia: A Comparison of Mars and Earth

    https://www.feynmanlectures.caltech.edu/I_09.html “Weight and inertia are proportional, and on the earth’s surface are often taken to be numerically equal, which causes a certain confusion to the student. On Mars, weights would be different but the amount of force needed to overcome inertia...
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