What is Roller: Definition and 313 Discussions

Roller skating is traveling on surfaces with roller skates. It is a recreational activity, a sport, and a form of transportation. Roller rinks and skate parks are built for roller skating, though it also takes place on streets, sidewalks, and bike paths.
Roller skating originated in the performing arts in the 18th century. It gained widespread popularity starting in the 1880s. Roller skating was very popular in United States from the 1930s to 1950s, then again in the 1970s when it was associated with disco music and roller discos. During the 1990s, inline outdoor roller skating became popular. Roller skating has often been a part of Black and LGBT history in particular.
Sport roller skating includes speed skating, roller hockey, roller derby, figure skating and aggressive quad skate. It is also widespread as a hobby.

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  1. W

    Direction of reaction of a roller

    Homework Statement for no 4 , why the reaction force also act downwards ? as far as i know roller can only support the surface perpendicular to it upwards ... but not downwards... for no 5 , why the recation force acts upward only ? why not also downards?Homework EquationsThe Attempt at a Solution
  2. R

    Centripetal Forces and Roller Coasters

    1. A roller coaster is designed with a clothoid loop that has a radius of 12 m at the top. For comfort, the apparent weight of a rider at the top of the loop must be 0.400 normal weight. What is the speed of the car at the top of the loop? 2. Fn = 0.400(Fg) Fn = 0.400(mg) mv2 / r = Fn + Fg...
  3. A

    Bearing loads for roller skates or skateboards

    I'm trying to determine load ratings for a deep groove roller bearing for use in a roller skate. I suspect I'll be looking at 100kg x 9.8N / 4 (2 bearings per wheel, likely only every to have a single set of wheels, front or back - 4 bearings - on the ground) * 2 (but this could be a landing!)...
  4. D

    Tapered Roller Bearing - Static Radial Rating

    I'm evaluating whether indirectly mounted Tapered Roller Bearings (http://goo.gl/FpOEri) are suitable to withstand a given radial and axial loads in both static and dynamic application. I've managed to find the required dynamic load rating C_90 (or C_10) with the help of the book "Mechanical...
  5. C

    Determining speed and height on a roller coaster

    Homework Statement One car (m=80.0 kg) tracks through the roller coaster in the following diagram. As it passes point A, it has a speed of 50.0 cm/s. a) Determine the speed at points B, C, and E b) If the speed at point D is _______, determine it's height (ignore friction) Homework...
  6. J

    Centripetal force roller coaster problem

    Homework Statement A roller coaster car has a mass of 500 kg when fully loaded with passengers.(a)If the vehicle has a speed of 20.0 m/s at point A, what is the force exerted by the track on the car at this point?(b)What is the maximum speed the vehicle can have at B and still remain on the...
  7. N

    How Fast Will the Roller Coaster Car Be at the Top of the Loop?

    Homework Statement At one point in a roller-coaster, a single 300 kg car goes around a vertical, circular loop with a diameter of 24 m. It enters the loop at the bottom with a speed of 20 m/s. What will its speed be at the top? Homework Equations Kinetic Energy = 1/2mv^2 Gravitational Energy =...
  8. M

    How Can I Prevent My Aluminium Plates from Bending During Embossing?

    Hi I have a aluminium hand roller for embossing numbers onto aluminium. When I pass the aluminium plate through the roller, I end up with a kind of banana shaped piece of aluminium. Any suggestion on a jig I could add to the aluminium rollers Thanks
  9. hdp12

    Given Moment about a Pin and a Roller

    Homework Statement For my statics homework, we are directed to: Draw the free body diagram and use the force and moment equilibrium to determine the support reactions for the following systems I'm having a bunch of trouble with problem 4.10, which is displayed in the following picture I'm...
  10. H

    How can I create a simple latch mechanism using a roller chain for my project?

    I'm looking for a simple latch design. My project will have two roller chain sprockets positioned one above the other with about a two foot gap. A motor will turn one of the sprockets and the other is just an idler sprocket. A #40 roller chain will run around the two sprockets. Mounted just...
  11. F

    Conservation of Mechanical Energy on a Roller Coaster

    Homework Statement A roller coaster at an amusement park is at rest on top of a 30 m hill (point A). The car starts to roll down the hill and reaches point B which is 10 m above the ground, and then rolls up the track to point C, which is 20 m above the ground. (A) A student assumes no energy...
  12. D

    Statics Question -- Bar and roller resting on a circular surface

    Homework Statement [/B]Homework EquationsThe Attempt at a Solution [/B] Honestly, I don't even know how to begin this problem. I've drawn myself some free body diagrams, but I'm uncertain of all of them. The weight of the bar is just (0,-mg) at .9r from the pivot point. But I don't know how...
  13. S

    Solving for Speed on a Roller Coaster's Top of Hill

    Homework Statement A roller coaster car is going over the top of a 18-m- radius circular rise. At the top of the hill, the passengers "feel light," with an apparent weight only 60% of their true weight. How fast is the coaster moving? Homework Equations I think F=mv^2/ (r) F=ma The Attempt...
  14. C

    Constant g roller coaster loops

    I was reading this interesting article on different varieties of roller coaster loops, and I know nothing about calculus or ODEs, but I was wondering what the constant-g loop in section 3.2 would actually look like for some typical initial velocity. Is it conceivably possible for a rider to...
  15. S

    Torque and power requirement for roller

    We have roller setup which is to be driven by a motor. The roller dia is 90 mm. A shaft which is connected to its end is 25 mm of dia. The roller weight is around 10 kg. On the periphery of the roller there are some 40 kgs of mass is acting. The roller rpm is 10. What is the torque required to...
  16. R

    Roller Coaster Loop: Solve for Height and Motion

    Homework Statement Hi, I am stuck on this thought experiment: A roller coaster of mass m starts on a inclined plane at a certain height, and then enters a circular loop, with radius r. At what height, h on the plane, must the trolley start in order to stop at the exact top of the loop...
  17. V

    What is diff in application of 3 & 4 roller plate rolling machine

    what is diff in application of 3 & 4 roller plate rolling machine. which type of rolling machine more usefule for 6 mm plate... & please suggest the ways to reduce the flatness of end portion after rolling ...
  18. R

    Constant Breaking force for roller coaster

    I really don't understand this: Consider a frictionless, 12000-kg roller coaster that starts at rest at the top of a hill, point A, 95 m high. It goes all the way the 75 degree steep hill and coasts horizontally (for an unspecified distance) before reaching point B (0 m high). The entire ride...
  19. A

    Reaction Forces on a Frame With Roller Joint and Pin Joint

    [b]1. Hi, The problem: A roof support frame has various leadings on it. The frictionless pin joint at points A has vertical and horizontal reaction forces. The rollers at point B allow free movement in the horizontal direction and has a vertical reaction. a/Calculate The total Horizontal...
  20. N

    Discover the Theory Behind Roller Coaster Toys and Satisfy Your Curiosity

    What theory is used in roller coaster toy?? Can someone explain fully for me? Thanks!
  21. G

    JollyOlly's book 'A Roller Coaster Ride through Relativity'

    I'm concerned about your book. I got up to this part: And I got very concerned. Although what you say is true, the fact that you put the last part of the quote in a box, like you did for what you called the Fundamental Principle and its restated version, gave me the impression that you...
  22. P

    Max Velocity and Height of Roller Coaster Track

    Homework Statement A man starts riding on a frictionless roller coaster track at initial velocity v_{o}. At point A the radius of the bend is r. a) What is the maximum v_{o} such that when the cart gets at point A it stays on the track? b) Using you answer in a) what should h' be such that...
  23. M

    Roller coaster without gravity

    Homework Statement A roller coaster is designed in an area of the park that is gravity-less. The roller coaster will accelerate a cart with a total mass of 10kg, from the initial position as shown in the figure to point A. After passing through point A, the cart will no longer speed up and...
  24. T

    Calculate Nip Roller Torque for T1=10 lbs and T2=20 lbs

    I'm wondering if someone could help me. I'm curious what the torque in each driven roller would be in the following picture. Say for example I want the input tension(T1) to be 10 lbs and the output tension(T2) to be 20 pounds. Assume the radius for each driven nip is the same. Also assume...
  25. K

    Taper roller bearing mouning configurations

    Hello, I see that the TRBs (Taper Roller Bearings) are paired usually in 'X' or 'O' configuration. Can somebody pl. share the situations that drive towards choosing a specific configuration? Thanks.
  26. H

    Roller coasters: would we fall out without restraints?

    I ask because as you might have heard recently a person fell out of a roller coaster when her restraint came open last week in Ohio. I was always told that the physics of these ride designs made it so that the people would be safe even without a restraint. I'm skeptical about a few things...
  27. O

    Solving Roller Coaster Physics Problems - Centripetal Force/Acceleration

    Hello, When doing simple physics problems involving roller coasters, I'm having trouble finding the centripetal force/acceleration. When the object is at the bottom of the loop, I understand the centripetal acceleration relies on the normal force. However, when the object is at the top...
  28. V

    Paper roller question - FBD etc

    Dear friends... During the last months I am puzzled by the following problem and I would like to kindly ask for your assistance, There is a device that I am trying to analyse and although the results do make some sense it seems that the experiments that I have done fail to replicate...
  29. B

    How do I calculate g-forces on a roller coaster?

    Homework Statement I have constructed a small scale roller coaster for my physics class. I was given the task of finding a track design with a safe and enjoyable ride. For times sake I plan to simply calculate the changes in g-force. I am using a hotwheels car and plastic track. I simply need...
  30. N

    Does a roller coaster have both kinetic and potential energy at every point?

    Hi, I am calculating energy (if there were to be no energy lost due to friction, etc) for this roller coaster. I understand that at point A there is only GPE and that at point E there is only KE. I was wondering if there would be both KE and GPE at point B and C. Would there be both KE and...
  31. S

    How Does Roller Coaster Design Affect Cart Speeds at Loop Apex?

    Homework Statement Consider a roller coaster with length = 10m and mass 4000kg consisting of 5 identical carts. Ignore the length of the connector between the carts. Suppose the rolercoaster is on a track where it loses energy at a rate of 1300 J/m. The rollercoaster approaches a loop with a...
  32. S

    How Much Force Does a Lift Chain Apply to a Roller Coaster?

    Homework Statement THe length that the train is pulled up the lift hill is 120 meters. How much force did the lift chain apply to the coaster to pull it up the hill. Mass of the roller coaster = 4140 kg θ = 66° Homework Equations The Attempt at a Solution I Tried F=ma to get...
  33. N

    Kinetic and Potential Energy on a roller coaster

    Homework Statement A roller coaster starts at the top of hill that is 10 m high. If it is to barely make it to the top of a second hill that is 20 m high, how fast must the initial speed of the roller coaster be? Assume that the roller coaster is frictionless. Homework Equations KE =...
  34. C

    Roller Coaster Problem with KE and PE

    Homework Statement https://dl.dropbox.com/u/92857534/physicsproblem.png Note: Solving for part D and EHomework Equations Unsure. Langauge in the problem seems ambiguous. Perhaps (KE + PE)b = (KE + PE)a The Attempt at a Solution So I think it's done this way. From A to B and B to C, the...
  35. D

    Cam Follower Reaction Forces in Accelerating Roller Cart

    Homework Statement Cam followers are 25mm and 32mm in diameter. Mass is 4kg. Determine the reaction forces on all of the cam rollers when cart accelerates to the right at 20 m/s^2 Homework Equations The Attempt at a Solution (4kg)(20m/s^2)(.05m)/(.018m) = 222 N on small roller...
  36. A

    Rolling resistance, stiction calculation for pipe roller

    My ultimate goal is to spec a motor for a shop tool. It is a stand to rotate a glorified pipe. The pipes are quite large (up to 19,000lbs). The pipe will sit on four wheels. Two of the wheels are motorized. I have a good idea of the torque/hp needed to accelerate to the desired angular velocity...
  37. E

    Calculating the pressure force of a lever roller printing press

    Hello Everyone. I need some advice in calculating the pressure of a roller printing machine. The machine is operated by a geared rotating lever which moves the impression roller across a print surface. I had thought it was a case of using the equation for rolling friction to work out the normal...
  38. F

    What is the minimum turn radius for a roller coaster with given conditions?

    Homework Statement A roller coaster car (m = 750kg with passengers) starts with near zero velocity at the top of a 80m section of track that is inclined at -38 degrees from the horizontal. During the descent the average drag force acting on the car is 550 N. At the bottom of the descent is a...
  39. J

    Roller coaster energy question

    Homework Statement 1.What is the highest potential energy? 2.What is the biggest change in kinetic energy? 3.If the track is only designed to uses electricity to pull the cars up the first incline, does the rollercoaster experience conservation of mechanical energy? Explain your...
  40. P

    Find the reactions the pin A and roller D exert on the truss

    Homework Statement The rigid truss supports the loads shown. Find the reactions the pin A and roller D exert on the truss. All concentrated loads act on the pins joining the truss membersHomework Equations ƩMa= -5ft(3kips)-10ft(2kips)-.707(1kip)10ft+Dy(15ft) Dy=2.80 kips*ft The Attempt at a...
  41. B

    Physics: Cardstock vs. Plastic Tubes for Roller Coaster

    Im wonder if its better to make a rollercoaster from cardstock or plastic tubes? In terms of energy conservation.
  42. F

    Normal force max min constraints on a roller coaster

    Homework Statement passengers cannot have a normal force equal to 0 or greater than 4 times their weight. What are the heights H1 and H2. Coaster starts at H1 and and ends at H2. H1>H2 and there is a low point between the two hills defined as zero height. The radius of the curve at the...
  43. C

    How Does Roller Coaster Physics Calculate Velocity?

    1. A diagram of a roller coaster is given. In the diagram, there are 3 humps in the track. At the top of the first hump(point A) the height is 60m from the ground. Point B is at the bottom of point A and is 5m below the ground. (height from point A to B is -65m). From point B to point C is 64m...
  44. B

    Roller coaster friction problem?

    Homework Statement You're at the amusement park and your friend wants to go on the "Barrel of Fun," where the ride is a cylinder with a vertical axis. You stand against the wall and after the ride is spinning fast enough, the floor drops out beneath you. What is the minimum coefficient of...
  45. N

    Centripetal Force and Roller Coasters

    Homework Statement A) A roller coaster has a vertical drop but followed by a loop. The total vertical height of the drop is 66m. It starts as a steep slope at an angle of 75 degrees relative to the horizontal and then enters into a circular path of radius R. In order to stay below 4 times the...
  46. C

    Person sitting on scale on roller coaster

    Homework Statement A 120 pound person is sitting on a scale during a roller coaster ride. As the roller coaster goes over the top of a curve whose radius is 30 feet, the scale indicates a force of 25 pounds. The average speed of the roller coaster doesn't change while over this curve...
  47. J

    Finding speed of roller coaster at different points

    Homework Statement Homework Equations KE= 1/2 m v2 PE = mgy The Attempt at a Solution I'm not sure how to start this because there is no given mass. If I use a kinematics equation I don't have an acceleration.
  48. A

    Roller coaster change in acceleration?

    Homework Statement You have taken a job as senior hench-person with Dr. Caasi Notwen, arch-nemesis of James Bond. As with all of Bond’s enemies, Dr. Notwen would like to develop an overly complicated method of dispatching the British super-spy, so he has tasked you with designing a...
  49. H

    Calculation of Torque for Drive Pulley of Roller Conveyor

    Anyone can help me to calculate the Torque for Drive Pulley of Rolling Conveyor? The details below: - Roller Conveyor : length = 18m (speed of the belt conveyor is 2.5m / sec) - Conveyor consists of 25 roller, 1 drive pulley & 1 tail pulley - Total load of the conveyor : 5,500 kg To move...
  50. J

    Rotational motion roller coaster problem

    Homework Statement Homework Equations ƩF = ma = (mv2) / r The Attempt at a Solution For part A: Fn - Fg = (mv2) / r Fn = ((mv2) / r ) + mg Fn = (500x20^2) / 10 + 500x9.8 Fn = 24900 This seems too high to be true. But I'm unsure of what I did wrong. I know the normal force...
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