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. billtodd

    The ratio between two horizontal speeds in this pendulum arrangement

    From the forces equation I can only understand from it that the forces' equations are:##N=Mg## and ##T\sin \theta=m\ell \ddot{\theta}##. But I don't know how to find the Torques' equations. Any help is appreciated. N=Mg ##Tcos⁡θ+N=mg
  2. M

    Is this projectile motion situation possible?

    Hi everyone, I have created a question which I thought would have a single simple solution, but have noticed there are two possible answers. This makes me think that the question's scenario is impossible with the numbers I made up. I think we all can agree that the horizontal component to...
  3. A

    Relative velocity of two objects: one on a circular path, one on a horizontal straight path

    In the question I assumed the velocity of the circular object to be : $$\vec v_A= v cos( \phi + \omega t) \hat i + v sin(\phi + \omega t) \hat j$$ where $$\omega = \frac{v}{R}$$ Velocity of the other particle is $$\vec v_B = v \hat i$$ Now magnitude of relative velocity comes out on...
  4. brochesspro

    B Finding Angle Between Fluid & Horizontal: Clarified

    I have been taught that in order to find the angle made by a liquid in a container with the horizontal, we use the fact that the free surface is perpendicular to the net force vector acting on the fluid (including the pseudo force vector for an accelerating container), however, if say the...
  5. M

    Horizontal force on a horizontal bar

    Tnet = 0 = Tcord-Twall-Tmass TLsinθ-2m(3/4L)-m(1/2)L TLsinθ= -(3/2)mL-(1/2)mL T=m/sinθ T= (1.52)/sin(39.7) = 2.38N
  6. Ben2

    Rise of Liquid from Horizontal Acceleration

    The only way I get this is to make a the vertical acceleration at the bottom corner and g the horizontal acceleration there. This is from Halliday & Resnick's Physics. I've been unable to find anything there or in REA's Physics Problem Solver. Thanks for any hints submitted.
  7. ogodwin

    Keeping a uniform bar in horizontal equilibrium

    I'm able to get the force of the top spring (6.75N upwards) by setting the sum of all forces equal to 0 as everything is stationary. Where I'm stuck is starting the second part of the problem. I initially tried setting the sum of torques equal to 0 using the top spring as a lever arm but unless...
  8. A

    B Hanging beads in vehicle turning on horizontal road (constant v and r)

    Neglect any forces within string, except tension.
  9. F

    Horizontal impulse on a ball at rest on a plane (with friction)

    Summary:: I'd like to check my understanding of standard problems where a billiard ball resting on a plane is hit horizontally at some height above its center So the situation is that a ball of mass ##m## and radius ##r## is at rest on a horizontal surface. There is friction between the ball...
  10. D

    Understanding horizontal shear in beam with vertical load

    In an I-beam, the shear flow is usually shown drawn as on the left, not as drawn on the right. I do not understand why. I do understand: The total horizontal shear force must be zero, consistent with statics.This is satisfied in both images. The vertical direction matches the direction of the...
  11. samy4408

    What is the Purpose of a Semicolon in a Sentence?

    can someone tell me what is the meaning of the horizontal line in the sentence ? thanks .
  12. Y

    Horizontal velocity of a basketball as it goes through the hoop

    hey i don't understand why my answers are incorrect, here is my solution i would like if someone can help me understand what I am doing worng and how i should solve this problem
  13. Einstein44

    Finding the horizontal shift of a function

    I've never actually done this, so I was wondering if someone could show me how this is done. One way I tried was by simply using ##cos^{-1}## in order to cancel the cosine, but that gave me a different value, so I assume this is not how you are supposed to do this. --> I know I am supposed to...
  14. L

    B Question about a horizontal sundial

    I am curious how the height of the gnomon in a horizontal sundial is dependent on your location. Why does it need to be different high depending on where you are? Does it have to do with how high the sun is in the sky depending on the latitude you are on?
  15. Leo Liu

    Notation in fluid dynamics: A circle with a horizontal bar inside

    I came across this notation when reading the wiki article on Venturi effect, which baffled me. Can someone please tell me its meaning?
  16. rudransh verma

    B Independence of vertical and horizontal motion

    It says when the ball is shot the can is released and they both hit each other at the same height ie they travel same distance down. But that is only possible when the ball starts it’s downward journey the same time as the can starts it’s own. Shooting a ball upward direction will give it some...
  17. applesoranges

    Mass swinging in a horizontal circle on 2 strings

    I have already solved this problem, just would like to double check something with you conceptually. I've got a negative result for the tension in the lower cord. Intuitively I think it is right, because the lower cord does not support the ball in its opposing the force of gravity. It actually...
  18. ayans2495

    Relationship between horizontal range and angle of launch

    I would like to conduct an experiment asking the question "how does the angle at which a projectile is launched vary with respect to the horizontal range it covers?" Ultimately, I'd like to prove that the horizontal range is directly proportional to sin(2(theta)). This will be done with the aid...
  19. Rubberduck2005

    Centripetal Motion problem -- A bead sliding around a horizontal loop

    To be honest I am a bit clueless first with how to interrupt this question I think the bead is going around a wall type thing where there is friction both in the up and X direction. Some hint to get some ideas running would be great
  20. S

    Tension of string acting on stone moving in horizontal circular motion

    Is it possible for the stone to move in horizontal circular motion just like in the picture? I try to draw the free body diagram of the stone and there are two forces acting on the stone, its weight (directed downwards) and the tension of the string (directed to the left). The tension will...
  21. khodournajem

    Minimum motor power for a mechanical horizontal sieving machine

    r = 2.5 l=10 cm angle = 0 (maximum connecting rode elongation) w = 0.5 (30 rpm) n=10/2.5 = 4 so the acceleration is 1.5×0.5×0.5(1 + 1/4 ) = 0.4 m/s friction force = 10*9.81*0.3 = 29.4 Newton. Crank force is the mass of the object into acceleration. So crank force = 10 × 0.4 = 4 Newton...
  22. rbh

    Body thrown at an angle to the horizontal

    The answer says t = Vb - Va/g. Shouldn't it be Va + V(from highest point to point b)/g ?
  23. N

    MHB Horizontal Asymptote of Rational Function

    Given f(x) = [sqrt{2x^2 - x + 10}]/(2x - 3), find the horizontal asymptote. Top degree does not = bottom degree. Top degree is not less than bottom degree. If top degree > bottom degree, the horizontal asymptote DNE. The problem for me is that 2x^2 lies within the radical. I can rewrite...
  24. S

    Determine horizontal separation of fabric from diffraction pattern

    Do I need to use formula to answer this question? Can't I just divided the horizontal distance in the picture by 2. so the horizontal separation of the thread is 54.8 / 2 = 27.4 mm? Thanks
  25. D

    Engineering Moments at the connections between a horizontal beam and the 3 vertical beams supporting it

    Say that I have a continouos beam resting on top of column spanning across 3 column. The applied load is UDL on the beam, here's how the BMD look like. My question is whether the connection between the beam and column need to sustain the moment ? Which point need to sustain the moment ? All 3...
  26. J

    Expressing horizontal velocity as a function of time for a wave

    This is more of a conceptual question. To find the horizontal velocity as a function of time for the above wave function, you take its partial t derivative and insert x=4. In other words the function would be -2.4sin(1-12t). Im wondering why you take the partial t derivative and not to partial...
  27. I

    Horizontal force F applied so the relative postion stays constant

    g=9.81 m2g=m1a, a=(m2/m1)g=0.8g F=0.8g x (M+m1+m2)= 0.8g x (21+5+4)= 0.8g x 30= 235.44 N. The answer key however indicate that the answer is 392N. This made me think that the tilt of m2 has something to do with it, but I can't see how much it will make F larger than the above answer.
  28. greg_rack

    Horizontal inflection point of a parametric polynomial function

    For ##x=-1## to be an *horizontal* inflection point, the first derivative ##y'## in ##-1## must be zero; and this gives the first condition: ##a=\frac{2}{3}b##. Now, I believe I should "use" the second derivative to obtain the second condition to solve the two-variables-system, but how? Since...
  29. T

    Correction of horizontal astigmatism in an anamorphic lens

    Hello, I need advice which lens should I use for correction of horizontal astigmatism in anamorphics lens which contains two prisms. Focal length which I need to be focused is about 3 meters. I am using this prisms pair with projector. When I display grid horizontal lines are not focused...
  30. D

    Quickest Route Between Horizontal Points using the Initial Velocity & Friction

    re: https://www.physicsforums.com/threads/is-it-possible-to-solve-for-t.996132/post-6421205 https://www.physicsforums.com/threads/is-it-possible-to-solve-for-t.996132/post-6421230 Would it be possible to find t and r via the exact same equations as found in posts #4 and #10, and then find the...
  31. Z

    Find the range of an object coming off an inclined plane

    Hey Everyone, my physics teacher has assigned us a task which involves predicting the range of a ball falling down an inclined plane into a free-fall, the equation for the final velocity of the ball down the ramp, accounting for rotational velocity has been provided, this is the initial velocity...
  32. E

    Solar radiation on a horizontal tank

    Hello everyone, I'm looking to estimate the variation of degassing on a horizontal tank of VC (vinyl chloride) due to solar radiation. The feed flow is continuous but the outlet is batch flow. So there is a lot of variation of liquid level in the tank (constant pressure). To avoid a lot of...
  33. greg_rack

    Horizontal asymptote of a parametric function

    I'll write my procedure: $$\lim_{x\to\infty}[\frac{(a-2)x^3+x^2}{ax^2+6x+1}]\rightarrow\frac{x(a-2)}{a}\in \mathbb{R}$$ And now, assumed that everything's correct, how do I assign ##a## a value for having that limit finite and ##\in \mathbb{R}##, and so an horizontal asymptote?
  34. U

    Finding the horizontal tan() lines of this equation

    I've been able to find the tangent line with most equations, but I don't have any idea how to do it with a range of values instead of being given a singular value.
  35. morrobay

    Flood drainage outflow rate from horizontal 1500m drainpipe at sump

    This 1500 m long , 2m diameter , 1m below flooded road surface from point at right side to sump at left side is horizontal. My understanding for sufficient drainage is a minimum fall, 1:100 required. Then with a gradient of .01 a pipe of this length should have a 15m fall. There is grating...
  36. F

    Mechanical Advantage of a pulley with horizontal effort

    How will the MA of a fixed pulley change if I apply the effort horizontally? Intuitively, I feel horizontal effort should be lesser effort than vertical effort.
  37. V

    Horizontal projectile motion lab

    This is how I think the set up of the lab should look like. I've decided the height to be y=1,5m. The length x is assumed to be 0.32m. where Voy =0m/s the time it takes for the marble to drop 1,5m is 0,55s the inital velocity of the marble is around 0,47m/s I Think I have the...
  38. H

    Horizontal force on glued surfaces

    I am conducting tensile test on a bigger scale. When the material breaks i have the maximum kilograms that can be a applied to the material. I pull horizontal in a rubber patches glued to a rubber sheet and i want to find the maximum tensile strength in the glue. How do i convert my 2000 kg pull...
  39. K

    I Horizontal Tension Force equation

    (not a homework question - I left education over 45 years ago) Hi, this just out of interest as I have been googleing this and can't find the answer I know the equation for tension force, for example a weight on a string, block on a ramp, etc. But is there something similar for a horizontal...
  40. SpaceThoughts

    Low friction horizontal rotating platform

    I am looking for a rotation devise like that one in this video below (from 00:40 seconds). Does anyone know where to get one, or have any idea about how to create a nice and stable rotation setup for experiments without too much hassle and DIY? A bike wheel won't do, a disk is better, because I...
  41. F

    Horizontal Circular Motion With Lagrange

    In the situation described in the problem, the mass is moving on a horizontal circular path with constant velocity. Wouldn’t this make L and U both constant? Then the Lagrange equation would give 0 = 0, which isn’t what I’m looking for. Any help would be appreciated.
  42. Justice Hunter

    B Need an Equation for converting Vertical to horizontal FOV

    This is a representation of a square, and a triangle that creates an angle between that square. In this case, the horizontal and vertical components to the Angle of View are the same. Now, change this square into a rectangle, and the relationship to the horizontal and vertical components are...
  43. Kaushik

    Tension of a rod rotating on a horizontal table about a vertical axis

    If a rod is on a table (horizontally) and rotating about an axis that passes through one of its ends and vertical to the table, what would be the tension on the opposite end of the rod (the end opposite to the axis) . In this post (Check this post out from Socratic QnA), the limits take while...
  44. centinela20

    How to calculate the horizontal shift?

    I don't understand what horizontal shift means. I believe that means calculate the horizontal component of a_cx. But when I do that a_{cx} is in terms only of the angle and the radius of the earth. But what I need is to include the 50 m vertical distance, so I think that maybe we need to use...
  45. Angelx26

    Santa's Sleigh (Newton's 2nd Law-1D) Acceleration, Horizontal Motion

    All I know is that it involves Newton's 2nd law F=ma. Im wondering if I use average acceleration (vf-vi)/time I'm not sure where else to go from here.
  46. karush

    MHB Apc.2.3.01 Horizontal Asymtope

    Ok this is what I posted on MeWe in MathQuiz I'm pretty sure this can be solved just by a quick look at the powers But probably I could of explained it better I know the book says to take the Limit...