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. M

    How Much Force Does a Horse Need to Pull a Sleigh?

    A hors og mass 509 KG Pulls a sleigh of mass 255 KG and both horse and sleigh accelerate 0.5 m/s^2. the coefficient of friction for the sleigh is 0.150 as it moves over the snow. Find the horizontal force that the horse must exert on the sleigh. Remember sleighs have two identical blades on the...
  2. C

    Why does drop time remain constant regardless of initial horizontal velocity?

    So in projectile motion, an object launched horizontally traveling over a certain displacement (Δx), fall time remains constant regardless of what this horizontal velocity was. I understand that in this equation: Δx = v(avg) × Δt as horizontal velocity increases, displacement also...
  3. D

    Horizontal tangent/point of inflection problem

    Homework Statement The function y=x(to the forth)+bx(squared)+8x+1 has a horizontal tangent and a point of inflection for the same value of x. What must be the value of b? Homework Equations I think you have to find the derivative, set it equal to 0 and solve for x The Attempt at a...
  4. N

    Weightless horizontal bar equilibrium

    The weightless horizontal bar in the figure below is in equilibrium. Scale B reads 4.15 kg. The distances in the figure (which is not to scale) are: D1 = 6.5 cm, D2 = 10.0 cm, and D3 = 5.0 cm. The mass of block X is 0.94 kg and the mass of block Y is 2.04 kg. Determine what the reading on scale...
  5. E

    Horizontal Force on Pivot Point

    Homework Statement http://img151.imageshack.us/img151/6641/torquebk4.jpg Homework Equations T=F*r F*X=Ia I=ML2/3 The Attempt at a Solution I was able to do part A easily enough, but I'm not quite sure where to even start with part B. I know that the force on the pivot point...
  6. A

    Find the magnitude of the horizontal force exerted by the lower hinge

    Homework Statement A symmetrical door of mass 27.5 kg is 5.44 m high and 2.46 wide. The hinges are placed at the very top and very bottom of the door. Find the magnitude of the horizontal force exerted by the lower hinge. Homework Equations Fd=Fd sum tau clockwise = sum tau...
  7. I

    Momentum and horizontal speed

    Homework Statement When tossed upward and hit horizontally by a batter, a .24kg softball receives an impulse of 2.7 N*s. With what horizontal speed does the ball move away from the bat? Homework Equations Here are all the equations that were in our notes for this section. p (momentum)...
  8. V

    Angular Speed of Door at Horizontal Position

    Homework Statement A truck has acceleration A. Its door has a width w and a heigth h. We want to find the angular speed of the door when it reaches the horizontal. (I attached the problem as an image) Homework Equations See solution attempt. The Attempt at a Solution There is a fictitious force...
  9. B

    Calculate Cable Tension in a Slanted and Horizontal Position

    Tension help? Consider the 59 N weight held by two cables. The left-hand cable is horizontal. What is the tension in the cable slanted at an angle of 51◦? Answer in units of N. What is the tension in the horizontal cable? Answer in units of N
  10. S

    Horizontal Speed of Fragment

    Homework Statement A 14.0-kg shell is fired from a gun with a muzzle velocity 160.0 m/s at 27.0o above the horizontal. At the top of the trajectory, the shell explodes into two fragments of equal mass. One fragment, whose speed immediately after the explosion is zero, falls vertically. What is...
  11. H

    How to find horizontal distance

    1. Homework Statement [/b] A plane is flying horizontally with speed 246 m/s at a height 4130 m above the ground, when a package is dropped from the plane. The acceleration of gravity is 9.8 m/s2 . Neglecting air resistance, when the package hits the ground, the plane will be. 3. directly...
  12. G

    Horizontal drag due to rain

    Homework Statement An automobile is traveling at speed of 80 km/h through heavy rain. The raindrops are falling vertically at 10 m/s and there are 7*10^-4 kg of raindrops in each cubic meter of air. For the following calculations assume that the automobile has the shape of a rectangular box 2m...
  13. E

    Forces on a body in contact with a horizontal plane

    1. The drawing shows a 27.4-kg crate that is initially at rest. Note that the view is one looking down on the top of the crate. Two forces, and , are applied to the crate, and it begins to move. The coefficient of kinetic friction between the crate and the floor is k = 0.313. Determine the (a)...
  14. B

    Projectile Motion - Horizontal Launch

    Homework Statement A stone is thrown horizontally at 5.0 m/s from the top of a cliff 78.4 m high. a. How long does it take the stone to reach the bottom of the cliff? b. How far from the base of the cliff does the stone strike the ground? c. What are the horizontal and vertical components...
  15. J

    Finding the horizontal distance that the cork flew

    Homework Statement A 14cm diameter champagne bottle rests on its side on top of a frictionless table. Suddenly, the cork pops and the bottle slides backward for a distance of 22 cm in .42 s. If the mass of the bottle is 500 times the mass of the cork, find the distance from the original...
  16. C

    Solving for Horizontal Distance and Time in a Vertical Drop Problem

    Homework Statement A daring ranch hand sitting on a tree limb wishes to drop vertically onto a horse galloping under the tree. The constant speed of the horse is 12.0 m/s, and the distance from the limb to the level of the saddle is 2.00 m. What must be the horizontal distance between the...
  17. M

    Achieving Horizontal Motion of a Crate: A Physics Challenge

    Homework Statement The person wants to cause the 200N crate to start sliding toward the right. To achieve this, the horizontal component of the force exerted on the crate by the rope must equal 0.35 times the normal force exerted on the crate by the floor. [[[[[[[[[ + [...[ + [...[+...
  18. K

    Solving Projectile Motion: Horizontal & Vertical Distances

    Homework Statement A projectile is fired at an angle of 60 degrees above the horizontal with an initial speed of 300 m/s. Calculate A) the horizontal distance traveled and B) the vertical height attained in the first 6 s. Homework Equations The Attempt at a Solution I did...
  19. science_rules

    Understanding horizontal and vertical components of a falling object

    I want to understand this: In the case of a dropped object, the horizontal component of the velocity with which the object hits the ground is not the same thing as the horizontal velocity itself, am i right? The horizontal component of the velocity when the object hits the ground means the...
  20. N

    Cathode Ray Type Question - Electron being moved by horizontal plates

    Homework Statement An electron is accelerated horizontally from rest in a television picture tube by a potential difference of 5710 V. It then passes between two horizontal plates 6.45 cm long and 1.24 cm apart that have a potential difference of 249 V (see figure below). At what angle q...
  21. Z

    Visualize Horizontal Motion: Draw Diagram & Graphs

    Draw A motion diagram A postion-versus-time graph, and A velocity-versus-time graph. A pitcher winds up and throws a baseball with a speed of 40 m/s. One-half second later the batter hits a line drive with a speed of 60 m/s. The ball is caugh 1 s after it is hit. From where you are...
  22. N

    Normal force on horizontal plane

    Homework Statement Lets say that a person called A rides his motorcycle. When this person turns, he tilts his motorcycle on a horizontal road. Is the normal force still normal to the surface or does it point in the same direction as the person sitting on the bike? The Attempt at a Solution...
  23. T

    How to Calculate Horizontal Projection Distance with a Fixed Angle and Velocity?

    Homework Statement A firefighting crew uses a water cannon that shoots water at 25.0 m/s at a fixed angle of 53.0 degrees above the horizontal. The firefighters want to direct the water at a blaze that is 10.0 m above ground level. How far from the building should they position their...
  24. W

    Horizontal acceleration of a plane with constant vertical velocity

    Homework Statement On takeoff, the combined action of the air around the engines and wings of an airplane exerts a 7049N force on the plane directed upward at an angle of 58.7 above the horizontal. The plane rises with a constant velocity in the vertical direction while continuing to...
  25. F

    Proving 45 degrees is optimal value for greatest horizontal range

    I'm still doing grade 12 physics, so my physics knowledge is VERY limited. So I have a question about proving that a projectile launched 45 degrees above horizontal gives the greatest horizontal displacement. I have to ideas to go about proving this: 1. Subbing Equations I have...
  26. T

    Calculating Horizontal Distance and Time for a Package Ejected from a Plane

    Homework Statement After a package is ejected from the plane, how long will it take for it to reach sea level from the time it is ejected? Assume that the package, like the plane, has an initial velocity of 220 mph in the horizontal direction. If the package is to land right on the island...
  27. A

    Projectile Motion Horizontal Displacement Equation

    Homework Statement A fire hose held near the ground shoots water at a speed of 7.5 m/s. At what angle(s) should the nozzle point in order that the water would land 3.0 m away? The attempt at a solution I remember from engineering there was a single equation you could use to find the...
  28. S

    Max height-2 balls-1 straight up-the other horizontal at an angle? yikes

    Homework Statement A ball is thrown straight upward and returns to the thrower’s hand after 4 s in the air. A second ball is thrown at an angle of 67◦ with the horizontal. The acceleration of gravity is 9.8 m/s2 . At what speed must the second ball be thrown so that it reaches the same...
  29. G

    Standing on a horizontal beam

    Standing on a horizontal beam! |\ | \ | \ rope | \ | \ |wall \ | \ |...beam...37* x |w a beam is being held up by the rope due to the friction of the wall. the beam has a weight W, and a man is...
  30. A

    Confusion with horizontal component of PROJECTILE MOTION

    Hai! Can anybody answer to me why the horizontal component of a projectile motion has no net force?Why is it move with constant velocity ? I know that motion doesn't need force but acceleration need force. But at the time a projectile motion started it motion ,why can it doesn't required...
  31. L

    Another Horizontal Displacement Question

    First off, I'm glad I stumbled upon this place. Secondly, taking physics as an online course is probably not the best judgment call I have made in recent times. However, I'm here now and I plan on sticking through with the course. My problems, however, are lying with the labs. Since they...
  32. I

    Find a cubic function that has horizontal tangents at two given points

    Homework Statement Find a cubic function ax^3 + bx^2 + cx + d whose graph has horizontal tangents at the points (-2, 6) and (2. 0).Homework Equations No idea.The Attempt at a Solution I realize that the trick in here somewhere is to work "backwards". I completed a problem earlier that asked me...
  33. L

    Determine the horizontal component

    An 18-g rifle bullet traveling 200 m/s buries itself in a 3.6-kg pendulum hanging on a 2.8-m-long string, which makes the pendulum swing upward in an arc. Determine the horizontal component of the pendulum's displacement. What I tried was find the momentum of the bullet, then find the...
  34. S

    Applied horizontal force homework

    Homework Statement Two veggieburger patties, in contact with each other, are being pushed across a grill. The masses of the burgers are 113 g and 139 g. Friction is negligible. The applied horizontal force of magnitude 5.38x10^-2 N is exerted on the more massiv burger. Determine a) the...
  35. RonL

    Horizontal Waterwheel (from: centrifugal force thread)

    Horizontal Waterwheel (from: "centrifugal force" thread) This is all over my head, but I'm in the water and I want to learn,:eek: Maybe you guys need a mechanical challenge to apply your classical physics to:rolleyes:. I know very little of what has been said, or how to make calculations...
  36. D

    Calculating Time for Ball to Start Rolling on Horizontal Surface

    Homework Statement Ball starts to slide with initial speed v0 = 6.5 m/s on horizontal surface. After what time will ball start to roll? Kinetic friction between the ball and the surface is 0.3. v0 = 6.5 m/s \mu = 0.3 I = 1/2 mr^2 Homework Equations I have solved this problem but I'm not...
  37. C

    Find the equation for horizontal motion

    a ball is thrown with v(initial)=5i+19.6j find the equation of the horizontal motion Homework Equations the problems asks for ymax and tymax and part b asks for the equations of the horizontal and vertical motions. Lost on the equations
  38. J

    I think you're right. I'll try to be more careful.

    A square tank 12 feet high having a perimeter of 40 feet is filled with water weighing 62.4 pounds per cubic foot. The total horizontal force on one side of the tank due to the water pressure is MOST NEARLY ________ pounds. A. 58,000 B. 45,000 C. 36,000 D. 13,000 The answer key says...
  39. C

    Finding a Vertical Force given friction and a horizontal force

    [SOLVED] Finding a Vertical Force given friction and a horizontal force Homework Statement Problem: A box with a weight of 50 N rests on a horizontal surface. A person pulls horizontally on it with a force of 10 N and it does not move. To start it moving, a second person pulls vertically...
  40. J

    Horizontal Range (with incline)

    [SOLVED] Horizontal Range (with incline) Homework Statement A ball is thrown up an (v0) incline. The ball is thrown at an angle phi from the incline and the incline has an angle theta with the ground. 1) Show the ball lands a distance R = 2{v_0}^2 sin\theta cos(\theta + \phi ) / (gcos{\phi...
  41. H

    Calc Projectile motion horizontal velocity

    Homework Statement Calculate any or all of the following: horizontal velocity, initial vertical speed, angular launch speed, launch angle, and maximum height all for an object with a mass of 7.3g that is projected 24.5m. Homework Equations The Attempt at a Solution V=d/t...
  42. H

    Calculation of Horizontal Velocity, Initial Vertical Speed

    Homework Statement Calculate any or all of the following: horizontal velocity, initial vertical speed, angular launch speed, launch angle, and maximum height all for an object with a mass of 7.3g that is projected 24.5m. Homework Equations The Attempt at a Solution V=d/t...
  43. Z

    Horizontal rotating rod with another mass attached

    Homework Statement A uniform rod AB, of length (2a) and mass (m) has a particle of mass (0.5m) attached to B. The rod is smoothly hinged at (A) to a fixed point and can rotate without resistance in a vertical plane. It is released from rest with AB horizontal. Find, in terms of (a) and (g), the...
  44. T

    Finding a value of theta for which a tangent line is horizontal

    Homework Statement Find the smallest positive value for `theta` for which the tangent line to the curve `r = 6 e^(0.4 theta)` is horizontal The Attempt at a Solution I tried to use the (r'sin(theta)+rcos(theta))/(r'cos(theta) - rsin(theta)) formula to get the tangent line, which I got...
  45. D

    Vertical vs Horizontal takeoff (VTO vs HTO)

    Supposedly taking off horizontally costs less and is more energy efficient than vertical takeoff. Aside from the issues of staging, and rocket vs. propeller, does anyone know why HTO is better than VTO?
  46. J

    Projectile horizontal distance

    When you have a basic projectile problem, What is the easiest way to find a specific horizontal distance in the problem.( other than the full horizontal distance that the projectile travels) Say you know the height (y) but want to find the distance (x).
  47. L

    Why Objects Shrink at High Speeds: Exploring Horizontal Distortion

    Why, when nearing the speed of light, do objects appear to be shrinking to someone in a different frame of reference? I understand time dilation, but not the horizontal distortion.
  48. N

    Horizontal Tangent Line

    Homework Statement Find all points on the graph of the function at which the tangent line is horizontal. f(x) = 2sinx + (sinx)^2 Homework Equations Hi guys I have an issue. I do not know how to approach this problem. I know the chain rule but I still do not know how to solve the...
  49. B

    SHM horizontal spring mass system

    This problem states that a mass m is attatched to a spring with spring constant k and is pulled aside a distance A from its equilibrium position x=0. a) what is the speed as it passes the position x=0? I know that at A and -A v=0 and at x=0 v=max, but I can't remember how to get an equation...
  50. B

    Finding Horizontal Tangent Lines of an Equation

    The problem is to find the horizontal tangent lines of an equation. Here's my attempted differentiation. y^2 = x^3 - x + 1 {dy/dx} = (3x^2 - 1)/(2y) Correct, or no? i'm going to need more help going forward even if that is right, I just want to make sure it is.
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