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. K

    Horizontal component of an electric field at origin

    Homework Statement Calculating the horizontal component of an electric field at the origin of a semi circle. The image link is: http://imgur.com/SXYs4Rp The Attempt at a Solution I've tried using the formula k∏(Q)/r (8.98755*10^9)∏(-7.85*10^-6) / .113 = -1.961 * 10^6. Can anyone see...
  2. P

    Projectile Motion w/o Horizontal Givens

    Homework Statement A soccer player kicks a rock horizontally off a 40.0m-high cliff into a pool of water. If the player hear the sound of the splash 3.00s later, what was the initial speed given to the rock? Assume the speed of sound in air to be 343 m/s. I wrote down givens in the...
  3. S

    Horizontal force on a post in a Hammock

    Your friend of mass m sits in a hammock that is suspended between two vertical posts separated by a distance d. If the hammock dips a distance h below the height l at which the hammock is secured to the posts, what is the horizontal force on each post due to your friend? Use g for the...
  4. R

    Particle with horizontal velocity and vertical acceleration

    1. A particle moving at a velocity of 6.5 m/s in the positive x direction is given an acceleration of 0.9 m/s^2 in the positive y direction for 2.9 s. What is the final speed of the particle? Homework Equations v= vi +at The Attempt at a Solution v= 6.5 + (.9)(2.9)= 9.11 m/s...
  5. R

    Vertical acceleration and horizontal velocity

    1. (a) A particle travels horizontally between two parallel walls separated by 18.4 m. It moves toward the opposing wall at a constant rate of 9.4 m/s. Also, it has an acceleration in the direction parallel to the walls of 3.6 m/s^2, what will be it's speed when it touches the wall? (b)At...
  6. D

    Rolling a spaceship along its horizontal axis

    This is probably a silly question, but I want to make sure I get it right for a story I'm writing. I want to roll an elongated spaceship "around" it's horizontal axis (as opposed to flipping it end over end). Is it equivalent to say "along" the horizontal axis? In this case, I'm assuming...
  7. D

    Find points where tangent line is horizontal

    Homework Statement Find the points on the graph of x3-y3=3xy-3 where the tangent line is horizontal Homework Equations y = f(x) so implicit differentiation must be used when taking the derivative of y (xy)' = xy' + y The Attempt at a Solution So if the tangent line is...
  8. T

    Understanding Horizontal Trig Graph Translations

    Quick question guys.. I understand how trig graphs work (cos, sin, tan etc.). What I don't understand is when there is a horizontal translation of say, pi/4, I notice that the graph moves, but I don't really understand how to know exactly how far to move. For example if your HT was pi/4 and...
  9. W

    Movable pulley and two connected particles on horizontal tables

    Homework Statement Two particles of masses 6 kg and 8 kg rest on two horizontal tables.The coefficient of friction between both particles and their respective tables is (1/2).The particles are connected by a smooth inextensible string which passes over smooth pulleys and under a smooth movable...
  10. H

    Horizontal velocity constraint in Engineering applications

    Case 1: An airplane should not exceed upper limit horizontal velocity while on takeoff roll(or even during taxiing on certain roads).V-Rotation(VR)is an indication of the maximum horizontal velocity,a nose-wheel can handle.Some people claim that nose-wheel has an upper limit to normal reaction...
  11. K

    Three identical blocks connected by ideal strings, Find Horizontal F

    Homework Statement Three identical blocks connected by ideal strings are being pulled along a horizontal frictionless surface by a horizontal force. The masses of the three blocks are 15.1kg , 19.8kg , and 36.0kg , Answer the following questions concerning the motion of the blocks. 1. If...
  12. N

    Two blocks and a massless horizontal spring question?

    [b]1. Two masses of m1 and m2 is connected by a massless undeformed spring rest on a horizontal plane.Find the minimum constant force Fmin that has to be applied on m2 so that other block get shifted if D is the coefficient of friction between blocks and surface [b]2. Homework Equations...
  13. M

    Work Done on Horizontal Tank pumping oil

    Homework Statement A gas station stores its gasoline in a tank underground. The tank is a cylinder lying horizontally on its side. The radius is 3 ft, the length is 14 ft, and the top of the tank is 10 feet under the ground. The density of gasoline is 42 lb/ft3 a) Consider a slice of gasoline...
  14. S

    Finding initial velocity given angle and horizontal displacement

    Homework Statement distance = 0.8meters angle = 55° gravity = 9.81m/s^2 \V_0 = ?, assuming that it leaves and falls back on the same horizontal plane. The attempt at a solution So we know for a fact that the initial velocity is supposed to be 2 m/s, according to the book at least. I tried...
  15. J

    Solving Physics on Own: Horizontal Force for Blocks

    Dear Forum Users, I am studying physics on my own, i am new to this forum, i am working every example in the book and i have a question. I hope that you are so kind to give me an explanation so that i can continue my chapter exercises. The question of the book is : What horizontal force must...
  16. D

    Forced Normal mode frequencies of 4 horizontal springs, 3 masses

    Homework Statement Hey guys. The title says it all pretty much. We need to find the normal mode frequencies of a driven/forced system containing 3 equal masses connected by 4 springs of equal spring constant k. Homework Equations F=m\ddot{x} Spring potential V = 0.5kx^{2}...
  17. Ackbach

    MHB Solving Holt Physics Prob. 49 Concerning Comp. Spring w/Friction

    Problem: A light horizontal spring has a spring constant of $105 \; \text{N/m}$. A $2.00\; \text{kg}$ block is pressed against one end of the spring, compressing the spring $0.100 \; \text{m}$. After the block is released, the block moves $0.250 \; \text{m}$ to the right before coming to rest...
  18. Petrus

    MHB Vertical and horizontal tangent

    I am currently working with parametric equation and trying to solve finding points on the curve where the tangent is horizontal or vertical. When I do with trigometry I get problem... And I need help to understand this. I know what vertical and horizontal means. exemple this one i am working...
  19. W

    Projectiles colliding on a horizontal plane

    Homework Statement A bullet is fired from a gun fixed at a point O with speed v m/s at an angle Θ to the horizontal, At the instant of firing , a moving target is 10m vertically above O and traveling with constant speed 42√ 2 m/s at a constant angle 45 degrees to the horizontal.The bullet and...
  20. R

    Calculating dA/dB ratio for horizontal log?

    In the figure, a 105 kg uniform log hangs by two steel wires, A and B, both of radius 1.25 mm. Initially, wire A was 2.50 m long and 1.80 mm shorter than wire B. The log is now horizontal. Young's modulus for steel is 2.00 × 1011 N/m2. What is the ratio dA/dB? I'm honestly at a loss for how...
  21. K

    About bode plot horizontal axis question

    I have a question I'm wondering in bode plot we write the horizontal axis w rad/sec what does this mean? is it normal scale 0.1 0.2 0.3 ... etc with equal distances?? it's clear not because it's drwan on semilog paper if it's the horizontal log w why then we write 0.1 ,0.2 ,,1 ...
  22. D

    Stress tensors on a horizontal bar

    Homework Statement A horizontal support bar has a downwards force F = 450 N applied near one end, as shown. The radius of the bar is c = 4 cm, and the length L = 1.2 m. The stress tensor σ at any point describes the components of stress in a particular coordinate system. For the coordinate...
  23. N

    Horizontal force on a pendelum - what drives it upwards?

    Two questions: 1) If you have a horizontal force in the x direction on a pendelum supported by a wire, then it will go upwards and in the x-direction. What is the vertical component which drags it upwards? Is it the normal force which adjusts itself along the wire to match the horizontal...
  24. B

    Calculating vertical velocity from discrete horizontal velocities

    Hello, I'm working with a 2 x 3D arrays of fluid velocity values (east-west -> u and north-south -> v) and would like to properly calculate vertical velocities (w) from them (n.b. this is not homework). This ultimately needs to go into a processing algorithm, so while symbolic math is...
  25. H

    Horizontal component of force without angle given?

    Homework Statement A person is dragging a 60kg block at a constant velocity over flat ground. The force applied by the person to the block has components that are up and to the right. The coefficient of friction for sliding the block over the ground is μk=0.60. Calculate the rightward...
  26. P

    Spring/block on horizontal plane SHM

    Homework Statement 1. Find the speed and acceleration when the kinetic energy is equal to half the potential energy 2. Find the minimum displacement between the points where the kinetic energy and acceleration are at half their maximum valuesHomework Equations mv^2=.5kx^2The Attempt at a...
  27. V

    Second moment of area about the horizontal axis

    Could someone help me on how to calculate the second moment of area of the beam in the figure below? Thank you
  28. P

    At what points on this curve is the tangent line horizontal?

    Homework Statement At what points on the curve y = (x^2)/(2x+5) is the tangent line horizontal? Homework Equations Quotient rule The Attempt at a Solution I figured out the derivative which is 2x(2x+5) - 2x^2 ----------------- (2x+5)^2 I also know that for the equation of...
  29. S

    Horizontal Force on a Gate Hinge?

    A door is attached to a frame by two hinges and is at equilibrium. All forces and torques are therefore balanced. The door has a mass of 10.5kg, a width of 1.1m, and the two hinges are 0.7m apart. Find the direction and magnitude of the horizontal force applied to the door by the top hinge? I...
  30. C

    Friction on horizontal rough surface (finding tension)

    Please refer to the image attached. For 20(b), I thought the tension can be calculated just by taking the weight of B, which is 0.05 x 9.8 = 0.49N? How come the answer is 0.42N?
  31. Z

    Leaning sticks on a horizontal surface

    Homework Statement A body is composed of two straight pins that are joined at a right angle. They have lengths α and β and the mass per unit length is ρ. When the body is balanced on a flat surface, as shown, how large is the normal force against the ground in the right point of contact? 4...
  32. C

    A mass of 30kg on a smooth horizontal table is tied to a cord running

    Homework Statement A mass of 30kg on a smooth horizontal table is tied to a cord running along the table over a frictionless pulley mounted at the edge of the table. A 10kg mass is attached to the other end of the cord. When the two masses are allowed to move freely the tension in the cord...
  33. P

    (2D problem) What angle will yield maximum horizontal range?

    Homework Statement A supply plane is flying at 60.0m/s at an altitude of 200.0m. What angle of flight will yield the maximum horizontal range for the dropped package? Homework Equations 1/2(g)(t)2. The Attempt at a Solution So far the only equations that i have, but may be wrong...
  34. N

    Proving the Motion of Point P: Vertical or Elliptical?

    https://www.physicsforums.com/attachment.php?attachmentid=56184&d=1362060936 https://www.physicsforums.com/attachment.php?attachmentid=56185&d=1362060998 https://www.physicsforums.com/attachment.php?attachmentid=56186&d=1362061038 Any help of how to prove this problem would be...
  35. T

    Horizontal force exerted by an engine

    Homework Statement I am only confused about question 2. The Attempt at a Solution I decided to use bernoulli's equation to find velocity at point 1. With velocity at point 1 and point 2 I can use conservation of momentum to solve for the force exerted. In this case there would be Fx...
  36. F

    Find the values where the tangent line is horizontal

    1. Find the values for x at which the tangent line is horizontal 2. f(x) = x + 2sinx 3. I found the derivative to be f'(x) = 1 + 2cosx I then set the derivative equal to zero and it came out to be 2cosx = -1, cosx = -\frac{1}{2} So the values of the horizontal tangent are 2∏/3 ± 2∏
  37. P

    Horizontal thrust at near buildings

    Hi In a demolition what is the horizontal thrust of the near buildings remain.? that is for calculate the scaffolding to support the near buildings of a demolition. I read somethingh of a 10 per cent of the dead weight of the walls of the building remain but I think is very conservative...
  38. B

    Simple horizontal harmonic oscillator with spring that has a mass.

    Hi, Consider a block of mass M connected to a spring of mass m and stiffness k horizontally on a frictionless table. We elongate the block some distance, and then release it so that it now oscillates. According to the theoretical study using energy methods, we see that the mass of the...
  39. F

    Finding Magnitude of Unkown Force on Rough Horizontal Surface

    Homework Statement A block of mass 100g is at rest on a rough horizontal plane. It has a massless rope attached to one end inclined at 20° above the horizontal. When the tension in the string is 0.5N the object is found to be in limiting equilibrium. Part A: Find the coeffecient of static...
  40. I

    Find Initial Velocity from Angle and Horizontal Distance

    Homework Statement "An athlete executing a long jump leaves the ground at a 30.0° angle and travels a horizontal distance 8.00m. What was the take-off speed?" Let ##x=## horizontal distance ##v=## velocity ##a=## acceleration Known: ##x=8 m## ##x_0=0 m## ##a_y=-9.8 m/s^2##...
  41. B

    Horizontal flight without wings

    Just curious as I saw a movie of one on TV I'm trying to understand how a cruise missile can fly? I can understand action v reaction in a rocket pushing against the mass of the earth I can understand winged flight and air pressure holding the craft up I can inderstand a hovercraft using...
  42. C

    Finding a plane's weight and horizontal acceleration at takeoff

    Homework Statement On an airplane's takeoff, the combined action of the air around the engines and wings of an airplane exerts a 8240-N force on the plane, directed upward at an angle of 75.0° above the horizontal. The plane rises with constant velocity in the vertical direction while...
  43. L

    Proton Suspension Between Horizontal Parallel Plates: Charge & Voltage

    1. A proton is suspended in a vacuum between two oppositely charged horizontal parallel plates. The separation between the plates is 2.60mm 2. I assume it uses E=vd/d, but I don't really know 3. what is the sign of the charge on the lower plate? what is the voltage across...
  44. A

    Horizontal spring with friction

    Homework Statement A spring with negligible mass has a constant of 105 N/m. It has been compressed horizantally with a 2 kg mass for a distance of 0.1m. If the mass has moved after release for a distance of 0.25m, what is the coefficient of kinetic friction between mass and horizontal surface...
  45. A

    Horizontal Velocity in Monkey-Dart Problem

    In the Monkey-Dart experiment (where a monkey let's go of a vine exactly the same time a dart is shot at him), the dart is known to reach the monkey because the distance from the vine to where he ends up is equal to difference between where the dart was aimed and where the dart ends up : both...
  46. M

    Calculating Average Speed of a Baseball in Horizontal Projectile Motion

    This is the problem word for word: A student throws a baseball at a large gong 48 m away and hears the sound of the gong 1.18893 s later. The speed of sound in air is 330 m/s. What was the average speed of the baseball on its way to the gong? (For simplicity, assume its trajectory to be a...
  47. O

    Vectors - write ordered triples in vertical or horizontal form?

    A= i +j+k A=(1,1,1) can I write in vertical as shown? is there any difference between them? Thank you
  48. B

    Projectile Motion - motion on a horizontal surface

    Projectile Motion - motion on a horizontal surface please help! Homework Statement Isaac Newton shot a dirty snowball 76m across a horizontal field. It passed directly over Edmund Haley's head, and was in the air for 7.6s. How high did it get above the field? Answer in m. Homework...
  49. P

    Max horizontal displacement of a projectile

    Homework Statement A catapult is capable of firing a projectile with a velocity of 25 m/s, the catapult is surrounded by a wall of height 20.4 m what is the maximum distance measured from the wall, that the catapult projectiles are capable of hitting? Homework Equations...
  50. S

    Proper equation for converting horizontal to vertical force on a taper?

    So I was having a discussion with a buddy and we were trying to decide the proper equation to translate a horizontal force to a vertical force on a wedge. See my drawing below, if I apply a force at Fh, what is the equation for find out the force Fv? Thanks!
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