What is Roll: Definition and 179 Discussions

Rock and roll (often written as rock & roll, rock 'n' roll, or rock 'n roll) is a genre of popular music that evolved in the United States during the late 1940s and early 1950s. It originated from Black American music such as gospel, jump blues, jazz, boogie woogie, rhythm and blues, and country music. While rock and roll's formative elements can be heard in blues records from the 1920s and in country records of the 1930s, the genre did not acquire its name until 1954.According to journalist Greg Kot, "rock and roll" refers to a style of popular music originating in the United States in the 1950s. By the mid-1960s, rock and roll had developed into "the more encompassing international style known as rock music, though the latter also continued to be known in many circles as rock and roll." For the purpose of differentiation, this article deals with the first definition.
In the earliest rock and roll styles, either the piano or saxophone was typically the lead instrument. These instruments were generally replaced or supplemented by guitar in the middle to late 1950s. The beat is essentially a dance rhythm with an accentuated backbeat, almost always provided by a snare drum. Classic rock and roll is usually played with one or two electric guitars (one lead, one rhythm) and a double bass (string bass). After the mid-1950s, electric bass guitars and drum kits became popular in classic rock.Rock and roll had a polarizing influence on lifestyles, fashion, attitudes, and language. It is often depicted in movies, fan magazines, and on television. Rock and roll may have contributed to the civil rights movement because both African American and White American teenagers enjoyed the music.

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  1. Tanreom

    I How does a screw roll down an inclined plane?

    I was thinking about how various objects would slide down on an inclined plane, and I just couldn't figure this problem out. So let's say I have this screw or cone on its side, on an inclined plane. If friction exists, what would the motion of the screw be as it slides down the inclined plane...
  2. T

    B Probability in a roll of dice

    I was trying to calculate the probability of throwing only one six when throwing a pair of dice. Using the formula for non-mutually exclusive events : P(A)+P(B)-P(A,B) I get 1/6+1/6-1/36=11/36 but when I count all the 36 possibilities on paper I get 10/36 ways of getting only one 6. What am...
  3. Nexus99

    Bicycle wheel forced to roll around a vertical axle

    I had some idea to solve this problem but i can't understand where the moment M is directed and where the force/forces that has magnitude ##\frac{M}{d}## is/are directed. Can anyone help me?
  4. Addez123

    Calculating the expected value of a dice roll

    I write p(k) as: $$p(k) = 1/6, k = 2,3,4,5$$ $$p(k) = 2/6, k = 6$$ Is that wrong? Because then the expected value becomes $$1/6 * 4 + 2/6 * 6 = 8/3$$ While my book says 11/3
  5. omega_minus

    Surface speed of a strip over a deflection roll

    Hello, I am trying to solve a problem at work that at first I thought was easy but has proven trickier than I originally thought: If I have a strip of material traveling in a straight line and it is tangent to a roll turning below it, the roll would need to turn at the surface speed of the...
  6. S

    Guide to Aircraft Coordinates: Roll, Pitch & Heading

    Hi, I’ve read a set of coordinate elements: „roll, pitch and heading“ for aircrafts. What’s the difference to „roll, pitch and yaw“? Senmeis
  7. G

    B Calculating Dice Roll Probability: Learn Basics with Frank

    Hello, I am trying to learn the basic concepts of calculating probability as it pertains to dice rolling. I have searched the internet and not been able to figure it out. If I have a regular 6 sided dice and I want to know the probability of rolling a 3, I know its 1/6 or 16.6%. This is...
  8. W

    I Predictive Dice Roll: Physics & Accuracy

    Hi, 1. A multi-sided dice - 20 sides for example. Highly accurate each side equal size. 2. Dice dropped from a machine - with same starting orientation. 3. Dropped in a vacuum from same height each time. 4. Dropped onto a very flat surface - 90-degree angle. Now given I have tried to make...
  9. CanFan

    B What sort of can would roll the fastest?

    Hello, I'm new here so apologies if this is in the wrong place! I was wondering, hypothetically, what sort of canned food would roll the fastest (assuming the ramp remained constant and the can couldn't be altered)? I've been looking this up and I know a solid can would roll faster than an...
  10. R

    Rotation of a roll by a driving wheel

    The bigger circle is a hollow cylinder (steel) with a length of 0.6m and a diameter of 0.133m and a mass of 8kg. The 2 smaller circles are rubber wheels with a diameter of 0.080 and mass of 0.2kg. Both the roll and the wheels have ball bearings and are mounted on a shaft. On both the shafts of...
  11. ubergewehr273

    I Paper roll unwinding in jerks

    I came across a problem regarding a paper being rolled into a tube. When a piece of paper is rolled into a tube and then left to unwind, it is always seen that the unwinding happens in jerks and not smoothly. Why is it so? What I have thought (and thanks to some discussions on reddit), that...
  12. A

    MHB Calculate Probability of Successfully Rolling 5 Times

    I'm sorry if it's the wrong forum. I'm just doing a project with little experience in probability, and it's really important for me that the method I use is correct, so I just preferred to ask someone that has some idea on the topic. If you were so kind to explain the method or at least tell me...
  13. S

    Velocity, acceleration, jerk, snap, crackle, pop, stop, drop, roll....

    Edit: I see this was discussed in the related thread sorry for a repost. If acceleration causes a change in velocity, and jerk causes a change in acceleration, snap causes a change in jerk, crackle causes a change in snap, pop causes a change in crackle, stop causes a change in pop, drop causes...
  14. S

    Yaw, pitch and roll vs. azimuth and elevation

    Hi, Yaw, pitch and roll are used to describe the movement of planes or ships. Azimuth and elevation are used to describe the pointing direction of a dish antenna. Can they be used exchangeably? I think two angles are enough for planes and ships, why 3? Owen
  15. Abhishek11235

    Distance over which friction acts to make object roll

    In Morin's textbook,he ask a problem of the work done by friction in making body roll if the body initially starts with pure translation (i.e sliding motion). However I didn't get require answer(via Work Energy theorem) and I gave up. I checked solution and I became confused. He tells that...
  16. S

    Mousetrap car won't roll on ground but will when being held

    I have made multiple mousetrap cars, and they've all have the same problem. They all have rolled when I held them however when I would put them on the ground they would not go. I think the problem may be a friction problem, however I'm not sure. I don't know what to do. Any advice/help would be...
  17. Hiero

    Number of valid ways to roll M dice with N sides

    Homework Statement Suppose we have M dice each with N sides. The dice are ordered, so that rolling (1, 2, ...) is not the same as (2, 1, ...) A valid configuration is one for which each number rolled is at least as large as the previous. (For instance, take M=N=2. (1,1) is valid, (1,2) is...
  18. E

    Trim and roll (or heel) for submersibles

    Hey guys, Im studying submarines and I was wondering when discussing buoyancy changes for submersibles what is meant by "changes in trim and roll or heel". What is trim/roll/heel? How should I picture it? Thank you!
  19. E

    Find the length of a roll of GI steel sheet given its weight

    Homework Statement I have a roll of galvanized iron sheet steel. Its width is 19mm and thickness 0.25mm Density 7850 kg/m^3 Weight of the roll is 75kg I want to find how long would be the roll if its unwound. Homework Equations Density D = M / V Length L = V / A Area A = Width * Thickness The...
  20. Mathman2013

    Elementary probability question: dice roll

    Homework Statement Lets say you role a single honest dice 12 times. Where succes is either if the die shows 4 og 1 eye. My question is what is the probability of sucess or failure? Homework EquationsThe Attempt at a Solution Is it binomial or conditional probability?
  21. srfriggen

    How many ways can you roll an 18 from 5 dice?

    Homework Statement How many ways can you roll an 18 from 5 dice? Assume the dice are different colors. Homework Equations Factorials The Attempt at a Solution I listed combinations of dice that would add to 18 as follows 66411 65511 55521 44442 33336 66312 65412...
  22. V

    Minimum friction to roll an imperfect sphere on an incline

    Homework Statement I have a sphere, it's imperfectly spherical, I put it on an incline and apparently it needs a minimum friction to start rolling or moving. Homework Equations I = 2/5 MR^2 torque = I*alpha = R x F The Attempt at a Solution [/B] before anything, I don't get why there's a...
  23. CrunchBerries

    Spinning disk, friction and pure roll

    Homework Statement [/B] A uniform solid disk of radius R is set into rotation with an angular speed ωi about an axis through its center. While still rotating at this speed, the disk is placed into contact with a horizontal surface and immediately released as shown in figure below (a) What is...
  24. C

    MHB A boulder roll down the hill

    Dear Every one, Here is the question. How to get started with this question? A spherical boulder of mass 90.2 kg and radius 20 cm rolls without slipping down a hill 16 m high from rest. (a) What is its angular momentum about its center when it is half way down the hill? (Enter the magnitude in...
  25. andrewkirk

    I A perfectly stiff wheel cannot roll on a stiff floor?

    I've been thinking about rolling motion, helped by @kuruman's excellent Insights article on the topic. A crucial insight from that article is that, when a wheel rolls along a flat surface, its axis of rotation is through the instantaneous point of contact with the ground, not through its axle...
  26. T

    If you roll when you hit the ground you feel less velocity?

    Rolls or brake falls slow down how fast your body hits the ground by well rolling.How does this decrease impacted.
  27. FallenApple

    B Simultaneous roll of Non Transitive Dice

    So say that we roll three of them and assume that the fates of the roll are all decided simultaneously. I've seen the baysean network analysis for games where one player goes first and another goes second. But what I'm talking about is a roll of three dice such that they have to land...
  28. A

    Roll Stability of static structures

    Hi, Maybe someone remembers how to determine the necessary conditions for a static structure to be stable and not to roll over. I know about the method when you imagine the structure has been rotated back an forth, and depending on how the center of mass takes higher or lower state the...
  29. D

    Do light and sound waves roll up and break like ocean waves?

    When sea waves approach the shore they roll up and break due to different velocities of water layers formed due to the gradual change in water depth. The highest wave peaks move faster than all other layers and thus falls down. All other layers fall the same way but in a delay. this ends up with...
  30. C

    How to Calculate when A Roll Back Would Occur on a Ski Lift

    Hello! First off, here is a video of what a roll back is: Here's my question: How could I determine how much of a load the lift is carrying for there to be a loss of friction between the haul rope (the cable) and the bull wheel (the main wheel at both the top and bottom terminals), causing...
  31. C

    Rolling Cylinders across a grid of bars

    Homework Statement A cylinder is placed on bars.The separation of each bar is l.The cylinder is then pulled with a force F through its center.Find the terminal velocity of the object.Assume l<<R and the ball rolls without slipping. Homework Equations 1/2 mv^2 +1/2 Iω^2 = kinetic energy Work is...
  32. T

    Power of roll forming machine

    How to calculate power of roll forming machine? Is there any theory for calculation? Actually i am designing 10 step roll forming machine, But confuse about power calculation...
  33. S

    Calculating Torque Needed to Roll up Mats

    I volunteer with an athletics group that has some large mats that they roll out for practice and I started thinking of a way for us old timers to roll them up at the end of practice. The mats are rolled up on a reel, that when empty is 14" in diameter, when full with the mats the diameter is...
  34. HaLAA

    Roll a fair die 5 times

    Homework Statement Roll a fair die 5 times, find the probability that the first two rolls have the same outcomes. Homework EquationsThe Attempt at a Solution The total outcomes is 6^5, I think we have 6^2 * 6 choose 2 /6^5 since the first two numbers are fixed and we can choose 2 numbers from...
  35. FallenApple

    I How can objects even roll?

    So in most of intro physics rolling questions, the masses are assumed to be rigid. So if I roll a sphere on frictional plane, it will move forward and the friction force will help stablize it until pure roll. However, how can there even be a friction force assumed in these problems? The...
  36. K

    Ball being hit starts to slide and roll

    Homework Statement [/B] A billiard ball of mass m and radius r is being hit and starts to slide on a surface with equivalent of friction μ. What is the friction force The distance to rolling only What is the energy loss in the sliding phase Homework Equations Kinetic energy of a solid body...
  37. Tone L

    I Roll Angle of a Ship: Simple Equation Explained

    I have been on the hunt looking for a precise equation that gives you the angle that a ship is displaced along its x-axis (roll). There is a somewhat simple equation:Roll angle (Θ) : Θ = Acos( ωt+ φ)------where A is the amplitude of the wave, ω is the frequency and φ is the phase chage. So...
  38. R

    B Calculating Probabilities of a dice roll

    I'm trying to figure out how to correctly workout the probability of rolling 3 6's if I roll 4 dice at a time. If I roll 3 sixes in a row, I don't bother with the last roll The order in which I roll them doesn't matter So here are my potential combinations Combination 1 => x 6 6 6 Combination 2...
  39. G

    MHB Die Roll & Coin Toss: Why 42 Possible Outcomes?

    A fair die is rolled twice. If the two results are the same, a coin is tossed. Why is the total number of different possible outcomes of this experiment $42$?
  40. S

    Roll 5 dice simultaneously

    Homework Statement Calculate a) P(exactly three dice have the same number) b) Calculate the conditional probability P(three of the dice shows six|two of the dice shows 5) Homework EquationsThe Attempt at a Solution a) Say we have 1 as the number we get for three dice. There is 1/6 chance of...
  41. 0

    Acceleration of Rest Point for Rolling without Slipping

    Let's ignore gravity in this problem for simplicity. For a wheel rolling without slipping on some surface, the rest point is the point at a given instant of time that is in contact with the surface (the rest point has zero instantaneous velocity). If the wheel is rolling at constant velocity...
  42. 9

    Finding roll, pitch and yaw angles

    Homework Statement I have three angles that relate the sensory body frame to the Earth centered Earth fixed frame: roll_ecef, pitch_ecef, yaw_ecef I have the longitude and latitude. Find the roll, pitch and yaw angles that relate the sensor body frame to the local North East Down frame...
  43. B

    Determine force that will cause cylinder to roll out of cart

    Homework Statement I've uploaded an image of the problem below. The problem states: Determine the value of P which will cause the homogeneous cylinder to begin to roll up out of its rectangular recess.The mass of the cylinder is m, the mass of the cart is M. Friction of the cart wheels i...
  44. S

    Technical Knowledge of Technologists in Rock n Roll Bands

    The mid-end and high-end rock n roll performance bands have technical people or technologists to help with equipment (electric guitars, amplifiers, and variety of devices used with them; modifications, and repairs). Exactly what do these technical know, and how do they learn it? There have...
  45. Y

    Ball roll down from the top of a rough spherical dome

    Homework Statement A ball is rolling down from the top of a rough spherical dome with negligible initial velocity and angular velocity. Show that the ball must slide before losing the contact with the dome. Homework Equations ΣF=ma Στ = Fr = Iα fs = μsN vcm = rω Δmgh = 0.5mvcm2 + 0.5Icmω2 I =...
  46. T

    Determine speed needed to cause rollover of car hitting ramp

    Hello, So my issue is as follows: You have a car going at a constant speed and the right side of the car hits a ramp which causes that side to elevate and cause the car to rotate about its x axis. What I need to figure out is how fast does the car need to hit the ramp to cause a rollover...
  47. E

    Load factor as a result of constant roll rate

    The fuel pressure load equation for an aircraft in a constant roll maneuver has the term (as a result of the roll maneuver): \frac{\dot{\phi^2}}{2g}R^2 where R - radius from center of fuselage g - gravitational constant \dot{\phi} - roll rate my question is where does the "2" next to the...
  48. H

    Yaw Pitch & Roll to spherical Theta & Phi

    hi guys, can someone please tell me how to find Theta and Phi from Yaw Pitch and Roll? I use my smartphone orientation sensor on a project and i need to calculate the smartphone's normal vector projection.
  49. Moossameli

    Collision Experiment: Why Roll Back? Magnetic?

    Look at this experiment: Why roll the balls after the collision back to each other? Are they magnetic?
  50. P

    Length of a plate after roll forging?

    Hello, I'm new here. so I hope I posted this question in the right section. For this problem, I have to compute a couple of parameters: An Aluminum plate (7075-O) (length 10 [m], thickness 10 [mm], width 40 [cm]) is reduced in thickness from 10 to 9,5 [mm]. The radius of the rolls is 25 [cm]...