Horizontal Definition and 978 Threads

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. manjuvenamma

    Rough horizontal surface and an inclined smooth plane

    An object rolls down a smooth plane (whose angle and length are given) starting from rest. At the end of the plane it reaches horizontal rough surface, it rolls again on this surface and comes to rest. Given the friction coefficient how do we calculate the distance traveled by the object on...
  2. C

    For which value of x horizontal Tangent Line

    For which value of x...horizontal Tangent Line Homework Statement For which value of x does f(x) = \frac{k}{ax^{2}+bx+c} have a horizontal tangent line? Homework Equations Quotient Rule? F'(x) = [g(x)a'(x) - a(x)g'(x)]/g(x)^2? The Attempt at a Solution Am I supposed to...
  3. P

    Horizontal and vertical independance

    hey guys, i studied "applied maths" in "high school" [the irish version!] we studied projectile motion and velocity vectors etc, we worked on the premise that gravity affects only the verticle velocity of the projectile so that: for a projectile given an initial velcoity both horizontally...
  4. C

    Improving Fly Ash Deposition in Horizontal Circular Ducting

    Hi all.. Currently I'm mess up myself with a study of an improvement of incineration fly ash deposition in horizontal circular ducting hapen in my incineration plant. This plant treated the hazardous industrial waste as a fuel using fludised bed reactor and silica sand as an innert...
  5. R

    Determine Speed of Plane Flying Horizontally

    Homework Statement A plane traveling horizontally passes overhead at a height h at t=0. at time t=t1 a sonic boom i heard. b.) Determine the speed of the Plane Ma=1/sin(pheta) pheta=arctan(h/x) Ma=1/sin(arctan h/vt) I think I've done it correct up to this point... Do i have to...
  6. T

    Vectors, Components and some Horizontal Force?

    Homework Statement A mass of 100kg is suspended by two ropes that make angles of 60° to the horizontal. If a horizontal pull of 200N, in a plane perpendicular to the plane of the other forces is applied find the tension in the ropes after equilibrium has occurred. m=60kg...
  7. O

    A block collides with a horizontal spring

    Homework Statement A moving 2.7 kg block collides with a horizontal spring whose spring constant is 356 N/m. The block compresses the spring a maximum distance of 13.0 cm from its rest postion. The coefficient of kinetic friction between the block and the horizontal surface is 0.24. What is...
  8. T

    What is the maximum horizontal distance it can jump?

    [SOLVED] The Flea Homework Statement A flea, jumping with its highest possible initial speed, can jump to a maximum vertical height of 1 cm. What is the time spent in the air by the flea during the vertical jump? What would be the time spent in the air if the flea were instead to leave the...
  9. S

    Sprint Acceleration and Time to Top Speed Calculation

    Homework Statement A world-class sprinter can burst out of the blocks to essentially top speed (of about 11.5m/s) in the first 15.0m of the race. a.) What is the average acceleration of this sprinter? b.) How long does it take her to reach that speed? Homework Equations The...
  10. A

    Tension with horizontal kinetic friction

    [SOLVED] Tension with horizontal kinetic friction Homework Statement In Figure, block 1 of mass m1 = 1.8 kg and block 2 of mass m2 = 1.3 kg are connected by a string of negligible mass. Block 2 is pushed by force of magnitude 20 N and angle θ = 39°. The coefficient of kinetic friction between...
  11. B

    Projectile horizontal motion Question

    Homework Statement A ball is thrown into the air with an initial vertical velocity of 5.0m/s in addition to its horizontal velocity of 25.0m/s, how far would the ball travel horizontally before it reached it's peak? Homework Equations vf = vi + at I've also tried vf = 1/2g +at...
  12. N

    Projectile and Horizontal Distance

    [SOLVED] Projectile and Horizontal Distance Homework Statement A projectile launched at an angle \theta to the horizontal reaches a maximum height h. Show that its horizontal range is 4h/tan\theta Homework Equations Can you help me figure out how to get this setup properly and what...
  13. J

    Work done during sandpaper application on horizontal surface

    1. a table is being sanded. in the process, the sandpaper is rubbed back and forth 30 times over a distance of 0.6m. it is pressed against the table with a normal force of 1.5N, and the coefficient of kinetic friction is 0.85. how much work is being done by the kinetic frictional force during...
  14. M

    Vertical and horizontal asymptotes of the curve

    vertical and horizontal asymptotes of the curve of f(x) = (x^2+x-6)/(9-x^2 ) are respectively : a) x=3,x=-3,y=-1 b)x=3,y=-1 c)x=3,y=1 d)x=-3,y=-1 i did the infinit limit to find the horizontal asymptote and i got -1 then to solve the vertical; 9-x^2 = 0 and...
  15. U

    Horizontal and vertical lines - star

    Hi all, I'm wondering why we see those horizontal and vertical stripes of lights when looking at a light source (see e.g. http://apod.nasa.gov/apod/image/0601/pleiades_gendler_big.jpg" ). Why are these lines of light present in the first place and why are they only horizontal and vertical in...
  16. E

    Fix Horizontal Line on Computer Screen

    Recently a thin black horizontal line appeared across my computer screen. At first it was there for a while then went away, now it seems to be permanently there. Anyone know why it is there or how to get get rid of it.
  17. P

    Finding coefficient of kinetic friction given mass & horizontal force?

    Homework Statement You use 30N (**Not 25 N, that was a typo) to slide a wooden box that is 12 kg across a floor at constant velocity. What is the coefficient of kinetic fricition? Homework Equations Ff=coeff of kinetic friction (mu k) m*g ?? not sure. The Attempt at a Solution...
  18. G

    SHM - Horizontal Spring Question

    1. A 41g object is attached to a horizontal spring with a spring constant of 15N/m and released from rest with an amplitude of 22.4cm. What is the velocity of the object when it is halfway to the equilibrium position if the surface is frictionless? Answer in units of m/s. Homework Equations...
  19. F

    Swinging on a rope minimum horizontal speed

    A hiker plans to swing on a rope across a ravine in the mountains, as illustrated in the figure, where L = 4.9 m and x = 2.7 m, and to drop when she is just above the far edge. At what minimum horizontal speed should she be moving when she starts to swing(in m/s)? I tried using the...
  20. Y

    The distance (not horizontal nor vertical) of a rock traveled in a projectile

    Homework Statement A small rock of mass m is kicked from the edge of a perfectly vertical cliff of height h, giving it an initial velocity ~vo that’s purely horizontal. The rock lands at a distance d away from the bottom of the cliff. The ground there is assumed horizontal and we neglect air...
  21. O

    Spring-mass oscillate in 1-D on frictionless horizontal surface

    We have a spring-mass system which oscillates in one dimension on a frictionless horizontal surface. We act an external force on the mass. F=kχo sin(ωt). Let x=Asin(ωt+φ),A>0 and ωο is the natural frequency of the system. a) What is the phase of the motion of the mass relatively to the phase of...
  22. D

    Mass pushed by horizontal force at constant speed on an incline

    3. A 52.3-kg trunk is pushed 5.95m at constant speed up a 28.0 degree incline by a constant horizontal force. The coefficient of kinetic friction between the trunk and the incline is .19 . Calculate the work done by a) the applied force and b) the force of gravity. Fy = N - mgcos28 = 0 Fx =...
  23. S

    Find the Phase of a horizontal spring

    Homework Statement An air track glider attached to a spring oscillates with a period of 1.5s AT t= 0s the glider is 5.0 cm left of the equilibrium position and moving to the right at 36.3 cm/s so from what the question i have determined that T = 1.5s x= -0.05m V_x = 0.363m/s t = 0 Find...
  24. P

    Box being pulled up a ramp by a horizontal force

    Homework Statement A box (mass = 50.0 kg) is being pulled up a ramp at an angle of (27 ⁰) by a horizontal force, (F→). Given that the coefficient of kinetic friction for the ramp is 0.3, find the force, (F→) on the box. What is the reaction force on the box due to the tramp? (Identify...
  25. S

    Where Will the Ball Hit the Floor of the Railcart?

    [SOLVED] a question a railcart moves along a railway at constant velocity v_0 with a ball attached to its ceiling. at t=0 the ball is drooped from the ceiling and at the same time the railcart breaks are pushed creating deceleration such that its velocity is: v=v_0e^{ -pt}\hat{x} . h is the...
  26. J

    Calculating Horizontal Force for Displaced Chandelier

    Homework Statement A 30 kg chandelier hangs vertically from a 4 m long wire. What is the horizontal force necessary to displace the chandelier 0.10 m either way? Homework Equations F=ma The Attempt at a Solution I tried to figure out the angle made by the change in the...
  27. D

    How Does Displacement Affect Momentum in a Frictionless Spring System?

    Homework Statement A block of mass m is attached to the end of a horizontally mounted spring as shown. The spring has a spring constant k and obeys Hooke’s law. The block is given an initial displacement xo, after which it oscillates back and forth without frictional effects. (a)...
  28. L

    Centripetal accel - airplane flying in a horizontal circle

    centripetal accel -- airplane flying in a horizontal circle... Homework Statement An airplane is flying in a horizontal circle at a speed of 116 m/s. The 77.0 kg pilot does not want his centripetal acceleration to exceed 6.00 times free-fall acceleration. (a) What is the minimum radius...
  29. M

    Friction and horizontal movement

    Homework Statement A block of mass m lies on a horizontal table. Suppose you push horizontally with precisely enough force to make the block start to move, and you continue to apply the same amount of force even after it starts moving. Find the acceleration of the block after it...
  30. P

    Calculate Horizontal Force at Bottom of 7m Ladder for 72kg Person

    Homework Statement A weightless ladder at 7m long rests against a frictionless wall at an angle of 65degrees to the ground. A 72kg person is 1.2m from the top of the ladder. What horizontal force at the bottom of the ladder is required to keep it from slipping? d= 7m m(man) = 72kg r(man) =...
  31. A

    A block on top of another on a horizontal surface.

    Homework Statement Its not a very difficult problem, and I really only need to know 1 thing about friction; anyways, here's the summed up problem: (my teacher enjoys making us use constants instead of numbers btw) A horizontal force F is applied to a small block (mass m1), and it slides...
  32. B

    Horizontal Speed of bullet fragment

    [SOLVED] Horizontal Speed of bullet fragment Homework Statement A 14-kg shell is fired from a gun with a muzzle velocity 125 m/s at 33o 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...
  33. T

    SHM - mass-spring system on frictionless horizontal surface

    Homework Statement A 250 g block is resting on a frictionless horizontal surface. The block is attached to a spring. The mass-spring system is compressed by a 2.5 N force and then released from rest. (a) The resulting oscillation has a 1.0 s period. What is the spring constant? (b) What is...
  34. C

    What is the Relationship Between Friction and Horizontal Force?

    Homework Statement There is a heavy box across the floor, and you apply a horizontal force just sufficient to get the box moving. As the box starts moving, you continue to apply the same force. Show that the acceleration of the box, once it gets started, is a=(us-uk)*g Homework...
  35. ~christina~

    A woman pulls a suitcasewhat is the angle with the horizontal?

    [SOLVED] A woman pulls a suitcase..what is the angle with the horizontal? Homework Statement A woman at the airport tows her 20.0kg suitcase at constant speed by pulling on strap angle theta above the horizontal. She pulls on the strap with 35.0N force. The frictional force on suitcase is...
  36. C

    Coefficient of Friction when applied force is not horizontal to surface?

    Homework Statement What would happen to the coefficient of friction if the applied force was not horizontal to the surface? Homework Equations Ff=_{\mu}FnThe Attempt at a Solution I am unsure of how to proceed with this question, but I am thinking that you can't have friction against a...
  37. Saladsamurai

    I want to find Max horizontal range without

    using \frac{v_0^2}{g_0}=R_{max} for this problem: You buy a toy dart gun and you want to calculate its Max Horizontal Range. You fire the gun straight upward and find that it takes 2.9 seconds for the dart to leave the barrel and then return to the barrel. Can this be done without the...
  38. S

    Verical and Horizontal Circles

    This is a general question and one that I cannot get an answer for. What is the difference between the 2? How do they alter how we approach to solve a problem for each type? Answers kindly welcomed
  39. N

    Calculating Horizontal Distance of Dart Fired by Child on Incline

    Okay here is the problem: A dart gun is fired while being held horizontally at a height of 1.55 m above ground level, and at rest relative to the ground. The dart from the gun travels a horizontal distance of 7.77 m. A child holds the same gun in a horizontal position while sliding down a 39.7...
  40. J

    What horizontal force is necessary to hold the bag in the new position?

    A 125 kg mail bag hangs by a vertical rope 3.3 m long. A postal worker then displaces the bag to a position 2.0 m sideways from its original position, always keeping the rope taut. a)What horizontal force is necessary to hold the bag in the new position? b)As the bag is moved to this...
  41. F

    Are any tangents to the graph f(x)=x^2-3x horizontal?

    "At what points, if any, are the tangents to the graph f(x)=x^2-3x horizontal?" I know how to figure this out using a graphing calculator and using the 'short-cut' (nx^n-1), but I can't do it using limits. Help! I'd like to use the equation lim x->a = f(x) - f(a) / x - a Thanks!
  42. M

    Horizontal projectile problem(revised)

    Homework Statement A person standing on a cliff throws a stone with a horizontal velocity of 15.0m/s and the stone hits the ground 47.0 m from the base of the cliff. A. How much time does it take for the stone to hit the ground? B. How high is the cliff? C. What was the impact velocity of...
  43. M

    How to Solve Horizontal Projectile Questions?

    Homework Statement a person sstanding on a cliff throws a stone with a stone horizontal velocoty of 15.0m/s and the stone lands on the ground 47.0m from the base of the cliff. a. how much time does it take for the stone to hit the ground? b. how high was the cliff? c.what is the impact...
  44. T

    Angle plus horizontal velocity,

    if an object is fired at a 20 degree angle and has a horizontal velocity of 30m/s, what is the vertical displacement, how long the ball is in the air, horizontal displacement, original velocity of the ball?
  45. D

    Pendulum problem: Horizontal force and work done

    Homework Statement A simple pendulum (sting has no mass, no air resistance) has a weight on the end of mass m (unknown). The string has a length A horizontal (and always horizontal) force, F, acts on the weight, but it moves so slowly that acceleration is 0. a)What is the work done by force...
  46. H

    Solving Physics Problems: Max Height, Velocity & Horizontal Dist.

    Homework Statement A man stands on the roof of a building of height 14.1 m and throws a rock with a velocity of magnitude 31.6 m/s at an angle of 25.0 above the horizontal. You can ignore air resistance. Calculate the maximum height above the roof reached by the rock. Calculate the magnitude...
  47. J

    Horizontal Projectile Motion Question

    Horizontal Projectile Motion Question...please help! 1. A ball is thrown horizontally from the top of a building 22.8 m. high. The ball strikes the ground at a point 52.1 m. from the base of the building. a. Find the time the ball is in motion. b. Find the initial velocity of the ball. c...
  48. J

    Tension is horizontal rope tied to hooks at each end

    Want to make sure I'm doing this right... it seems too easy Homework Statement A horizontal rope is tightly tied to hooks between two walls separated by a distance of 5m. A 100N weight is suspended from the middle of the rope and it sags so that the middle of the rope is displaced a...
  49. C

    Modeling of pendulum with external horizontal force

    Homework Statement In general, I know that the dynamic equation of pendulum is theta'' + (k/m)*thata' + (g/l)*sin(theta) = 0 , where k=friction co, m=mass, l=length of string, g=gravity. But if the pendulum is placed in a constant draft, the equation has to be changed. Assuming...
  50. A

    A football is thrown upward at a 43 degree angle to the horizontal

    A football is thrown upward at a(n) 43 degree angle to the horizontal. The acceleration of gravity is 9.8 ms^2 : To throw a(n) 77.8 m pass, what must be the initial speed of the ball? Answer in units of ms.
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