What is Horizontal: Definition and 978 Discussions

The horizontal branch (HB) is a stage of stellar evolution that immediately follows the red-giant branch in stars whose masses are similar to the Sun's. Horizontal-branch stars are powered by helium fusion in the core (via the triple-alpha process) and by hydrogen fusion (via the CNO cycle) in a shell surrounding the core. The onset of core helium fusion at the tip of the red-giant branch causes substantial changes in stellar structure, resulting in an overall reduction in luminosity, some contraction of the stellar envelope, and the surface reaching higher temperatures.

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  1. J

    Static Equilibrium Door question: Calculate Horizontal Forces

    Homework Statement A door, essentially a uniform rectangle of height 2.00 m, width 0.87 m, and weight 130.0 N, is supported at one edge by two hinges, one 35.1 cm above the bottom of the door and one 164.9 cm above the bottom of the door. Calculate the horizontal components of the forces on...
  2. Y

    Having trouble finding the horizontal velocity of the object rolling down a ramp

    Homework Statement I need to find the horizontal velocity of an object on a ramp where the first height is 5.0m and the second height is 3.0m? I also need to find the time it takes to fall from the ramp, and the distance it falls away from the ramp. I am only given the two heights, an initial...
  3. lpetrich

    Quark and Lepton Mass Matrices, Textures, Horizontal Symmetries

    Does anyone have any good introduction to theories of the quark and lepton mass matrices? Theories like textures and horizontal symmetry. My understanding of research into textures is that it often involves trying to make zero as many entries as possible in the mass matrices. Is that a fair...
  4. M

    Need to support horizontal spinning tire: turntable or thrust bearings?

    Hi everyone. I need to create a mechanism involving a 12" diameter horizontal tire, spinning at 3000RPM, with 2kg mass. The wheel will be attached to a spinning shaft. The only thing, I need to support the wheel from the bottom using flat bearings of some sort, so it can spin freely...
  5. F

    Is there Gravitational Potential Energy on a horizontal surface?

    Is there Gravitational Potential Energy on a horizontal surface? Example from Position 1 - 2
  6. B

    Horizontal spring-block system

    Can anybody derive and give the formula for the time period of a spring-block system placed horizontally having a spring with a definite mass 'm"? Considering it will still execute periodic motion or else what will be the physical nature of such a system?
  7. E

    Calculating g using horizontal uniform circular motion

    Hi! I’ve recently done an experiment that I didn’t completely understand and now it seems I’ve lost all my notes as well (the notes written down from the teacher’s board, with a formula I really need, but didn’t understand). This work is supposed to be completed during the summer holiday, so I...
  8. R

    Confusion about vertical polarization and horizontal polarization

    Could you please help me to understand some basic concepts about antenna polarization. The books I have are really confusing and do not have examples that I can learn from. Please look at the attached E plane radiation pattern image I attached (figure 13). The books image (figure 13)...
  9. F

    Sphere in a horizontal plane + Projectile movement

    Hello guys, how are you? Homework Statement An uniform solid sphere, that has 20mm of diameter and 8.4g of mass, its release at a inclined plane with 22cm of lenght. The inclined plane 'ends' in a table in which the ball starts to move horizontally. After leaving the table, that has 92cm of...
  10. O

    Finding the force up an incline given horizontal force

    Homework Statement I need help with part of a problem. I am having problems understanding just how to find the force up an incline when a horizontal force ("headwind") is given. Homework Equations The Attempt at a Solution When drawing a triangle to figure it out I draw the...
  11. N

    Covariant derivative along a horizontal lift in an associated vector bundle

    I am trying to familiarize myself with the use of fibre bundles and associated bundles but am having some problems actually making calculations. I would like to show that the covariant derivative along the horizontal lift of a curve in the base space vanishes (which should be just a matter of...
  12. A

    LaTeX Effective Ways to Add Horizontal Spacing in Latex Text for Pseudo-code Writing

    Hello guys, I'm trying to get some horizontal spacing into my text. I want to do this because I basically want to write a pseudo-code in my text, so I need every loop to start a bit further away from the beginning of the page than the previous one. I've tried \hspace, but it does not seem to...
  13. M

    Why does a horizontal (wheel vertical) gyroscope eventually fall?

    I was hoping someone could clear this up for me. I've been thinking about it a bit, and I am thoroughly confused. Here is what I have come up with so far. The situation: A horizontal (wheel vertical) gyroscope spinning counter clockwise held up at one end by a string. Now change views so...
  14. I

    Why Do Horizontal Motion Problems in AS Physics Challenge Students?

    I'm currently studying Edexcel AS Physics (a UK-based examboard), I'm comfortable with problems where there is no horizontal component (so when something is thrown/released in a straight line; e.g. a ball thrown upwards), but I really struggle with problems that include the horizontal...
  15. Z

    Horizontal Spring, Find Unstretched length

    Homework Statement A spring of stiffness 1500 N m-1 is stretched between two points 2 m apart. If the tension in the spring is 200 N, what was the unstretched length of the spring? And what is the energy stored in the spring when it is stretched between the two points? Homework Equations...
  16. L

    Help finding friction force of block moving across horizontal atwood's machine

    Basically we did a lab where you attach a pulley to the desk with a clamp and then have a friction block (three types: cork, plastic, and felt) attached to a string which is attached to a hanging mass. This basic setup is called an atwood's machine. The purpose of the lab was to identify the...
  17. T

    Amplitude of horizontal mass-spring system

    Homework Statement This is a horizontal mass spring system in a simple harmonic motion problem set. Vmax = 20 m/s F = 10 N m = 0.5 kg Find Amplitude (A) and spring constant (k) Homework Equations The Attempt at a Solution I could not figure out a way to solve this problem, and the only...
  18. S

    Horizontal spring, mass and nonconstant friction

    Homework Statement Hello! The problem is about spring with block attached to it. ( with spring constant = k) The system is on surface that has a friction μ increasing towards the direction of the blocks movement. Block is pushed -0,1m ( to the left ) from the equilubrium position and then...
  19. G

    Initial Vertical Velocity of a non - horizontal projectile (trebuchet)

    I need to find the initial velocity of a trebuchet launch. Data I have is a distance traveled of 11.1 m, time of 1.25 seconds, height of the sling straight up at 1.85 m. Equations I can use are V2 = V1 + a(t) , dy = V1(t) + 1/2(ay)(t)^2 , V2^2 = V1^2 + 2ad and viy = dy / t. Finding the...
  20. D

    How long is discus in the air and the horizontal distance traveled

    Homework Statement A discus is released at an angle of 42.0° with respect to the horizontal and a velocity of 28.0m/s. a)How long does it stay in the air? b)What horizontal distance does it travel? Homework Equations dv=1/2*at2 dh=Vh*Δt Kinetic equation d=Vi*t+ 1/2*at2...
  21. F

    Finding Potential Energy of a Swing When the Ropes Are Horizontal?

    Homework Statement A 45.0 kg child is in a swing that is attached to ropes 1.90 m long. The acceleration of gravity is 9.81 m/s2 . Find the gravitational potential energy as- sociated with the child relative to the child’s lowest position under the following condi- tions: a) when the ropes are...
  22. A

    Pivoted rod - impulse applied so no horizontal force on pivot

    Homework Statement There is a rod of length L pivoted on one end. It is originally at rest horizontally then released. When vertical, an impulse is applied to bring the rod to rest. Throughout the question I have worked out I = 1/3 mL^2 w= √(3g/L) at the vertical position and an...
  23. R

    Box being pulled across horizontal floor with friction

    Homework Statement Sam is pulling a box of mass 30kg on a horizontal floor with a force FT= <50N, 30N>. The frictional force acting on the box by the floor is 20N. A) By using Newton's second law find the acceleration of the block. B) What is the normal force acting on the block by the...
  24. J

    Calculating Tension of a bob moving in horizontal circles

    Could someone please look at the problem below and see if i am on the right lines of solving it? I am finding the whole subject of circular motion hard to get my head around and therefore not 100% confident in my workings. I have also attached my free body diagram. Homework Statement...
  25. A

    Horizontal Force in Pipe Bending

    Homework Statement Water enters a pipe and goes through a bend with a contraction from 40mm to 25mm then into the atmosphere. What is the horizontal force required to hold the pipe in place? Homework Equations I have either been given the following or have calculated them using the standard...
  26. B

    Moving objects vertically with horizontal pressure

    If you have some relatively small boxes next to each other you can pinch them with your fingers and lift them vertically. I would like to do this with big boxes, but I don’t know how to calculate certain things. I would like to make a frame with 4 plates on it which pressure the boxes...
  27. J

    Irregular polygons - Equal area under horizontal line

    I've been trying to find an algorithm for finding a line passing through any 2-dimensional polygon that will divide the shape horizontally or vertically into two sections that each have the exact same area, or rather exactly half the area of the whole. I've prepared some simple examples below...
  28. A

    Calculating the gravitational field due to a horizontal uniform thin disk

    Homework Statement Show that the gravitational field due to a horizontal uniform thin disc (thickness D, radius R and density r) at a distance h vertically above the centre of the disc has magnitude 2πGρd(1-h/(R2+h2)1/2) A pendulum clock in the centre of a large room is observed to keep...
  29. L

    Slit pattern, vertical or horizontal?

    This has already been asked: https://www.physicsforums.com/showthread.php?t=77835 It is a simple question but I am confused, if the slit or the slits are vertical the direction of the pattern is horizontal or vertical? Vertical: | | |...
  30. J

    Dynamics: Max horizontal speed of a collar with three restricting springs

    Homework Statement A 1.2-kg collar C may slide without friction along a horizontal rod. It is attached to three springs, each of constant k 5 400 N/m and 150-mm undeformed length. Knowing that the collar is released from rest in the position shown, determine the maximum speed it will...
  31. Z

    Find two points on an ellpise that have horizontal tangent

    Homework Statement The equation 5x^2 - 6xy + 5y^2 = 16 represents an ellipse. Determine two points on the ellipse at which the tangent is horizontal. Homework Equations The Attempt at a Solution I find the derivative of the equation: (-10x + 6y) / (-6x + 10y) = 0 iff...
  32. J

    Dynamics: max horizontal swing of a pendulum

    Homework Statement In an ore-mixing operation, a bucket full of ore is suspended from a traveling crane which moves along a stationary bridge. The crane is traveling at a speed of 3 m/s when it is brought to a sudden stop. Determine the maximum horizontal distance through which the bucket...
  33. X

    Horizontal projectile, NOT GIVEN INITIAL VELOCITY

    Homework Statement A cannon ball is fired horizontally off the top of a cliff that is 400 m high above the ocean. The ball hits the water 600 m away. With what speed does the cannon ball enter the water? Homework Equations I've tried using d_{x} = u_{x}*t d_{y} = u_{y}*t +...
  34. S

    Horizontal cable with one vertical point force

    Homework Statement Hang a weight (F) from the middle of a horizontal wire of length L, attached on both sides. The wire has an effective modulus (E) and effective area (A). Find an equation for the new length of the wire LF. (NOTE: Do not try to solve for a form LF =, this is too hard)...
  35. M

    Finding Horizontal Displacement for Spring Cannon Launch

    A spring cannon is located at the edge of a table that is 1.2 m above the floor. A steel ball is launched from the cannon with speed Vo at 35.0 degrees above the horizontal. (a) Find the horizontal displacement component of the ball tothe point where it lands on the floor as a function of Vo...
  36. D

    Finding out the horizontal force required to make an object move.

    Homework Statement An ice fishing hut weighing 52 N sits on a dry, frozen lake. What is the magnitude of the initial horizontal force required to make the ice fishing hut start sliding across the surface of the frozen pond Homework Equations μk = Fk/Fn or μs = Fs/Fn The Attempt...
  37. T

    Vertical, Horizontal and Oblique Asymptotes Explaining

    Homework Statement Explain why each of the following functions have or do not have vertical, horizontal, and/or oblique asymptotes: (a) f(x) = e-x x5 + 2/ x5 − x4 + x3 − x2 + x + 1 (b) k(x) = sin(1/x) arctan(x) Homework Equations The Attempt at a Solution For the first one, to...
  38. K

    Object sliding down horizontal, frictionless slope, crossing horizontal surface

    Homework Statement block A slides down an 8 m frictionless ramp that is curved 30 degrees above the horizontal. it then crosses a 4m surface that has a coefficient of friction that is 0.20. it then hits a ball and continues moving at 3 m/s. the ball is suspended from a string, kinda...
  39. B

    Vertical and horizontal motion

    When calculating vertical motion at an angle you use sin, when horizontal you use cos, I don't understand why.
  40. M

    Calculating horizontal force from disc magnet

    Homework Statement I want a box shaped robot to move on the ceiling. The robot sticks to the ceiling using magnets. I am attaching a picture. The red is a magnet. How do I calculate how much force is needed to move the robot horizontally? I know very little physics and I need to figure out how...
  41. A

    Horizontal Plane With Friction And Incline Plane With no Friction

    1. A body with mass m = 5 kg and initial velocity = 5 m/s moves along a horizontal plane with length 10 m, where the friction coefficient is μ=0.1, After passing the part with friction, the body moves up along a tilted plane which has no friction. What is the maximum height of body elevation...
  42. G

    Horizontal acceleration of a person

    Let's say that an athletic person of average height (1.75 m) and weight (75 kg) is strapped by the feet to a small motorized board. How would one go about calculating the maximum acceleration the person can sustain without falling backwards? There is no wind and the air density is at sea level.
  43. I

    Solving Sliding Object Down Ramp: Horizontal Forces Only?

    I went to ask my teacher for extra help and we were doing a problem about an object sliding down a ramp. When I calculated the Fnet I added all the forces together acting on the box but she said that you only take into account the horizontal forces. Any clarification would be much appreciated!
  44. F

    Parametric equations for vertical and horizontal circular motion

    Hello. I apologize if I put this in the wrong section. I got this problem with the assignment I am currently working with. I have to set the position function for motion as a parametric equation for motion in circular motion, horizontal and vertical respectively. While I do know the...
  45. B

    Horizontal Spring Problem, just need it checked

    A 3kg block is resting at the bottom of a ramp that is at a 37 degree angle with a coefficient of friction of .2. A spring at the bottom of the hill has a spring constant of 5000N/m. The block compresses the spring 8cm (so .08m) and is then released. The block slides up the ramp and then slides...
  46. D

    Caluclating tension in string that is moving in horizontal circles.

    Hi all, First of all I'd like to say thank you to you all for providing a great forum which has been a great help to me working through my ics home learning course. As i have learned on here and other places on the internet the information I have in my course materials is not always...
  47. Z

    ZIPLINE PROJECT, make object travel 7.4 meters and back on a horizontal zipline

    HELP PLEASE! I have to create an object that will travel a straight, horizontal zipline of 7.4 meters, and then travel back .4 meters to the starting point.. The object has to be all mechanical (no electric power source) and can't weigh more than 2 kg. It also has to be pretty cheap ($50) to...
  48. T

    Finding Horizontal Tangent Planes on S

    Homework Statement S is the surface with equation z = x^2 +2xy+2ya) Find an equation for the tangent plane to S at the point (1,2,9). b) At what points on S, in any, does S have a horizontal tangent plane? The Attempt at a Solution F(x,y,z): z = x^2 +2xy+2y F_x = 2x + 2y F_y = 2x + 2...
  49. X

    Elastic Problem. Aluminum Wire in Horizontal Circle

    Homework Statement An aluminum wire is 0.850 m long and has a circular cross section of diameter 0.780 mm. Fixed at the top end, the wire supports a 1.20-kg object that swings in a horizontal circle. Determine the angular velocity required to produce a strain of 1.00  10–3. Homework...
  50. S

    Kinetic Energy of a mass moving in horizontal circle

    Homework Statement A mass moves in a circular path that has a radius of 24.6cm on a horizontal frictionaless surface. If the centripetal force acting on the mass is 96.5N, what is the kinetic energy of the mass? r=0.246m Fc=96.5N Homework Equations He told us to use these and "play...
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