# What is Rolling ball: Definition and 64 Discussions

In topology, quantum mechanics and geometrodynamics, rolling-ball arguments are used to describe how the perceived geometry and connectedness of a surface can be scale-dependent.
If a researcher probes the shape of an intricately curved surface by rolling a ball across it, then features that are continually curved but whose curvature radius is smaller than the ball radius may appear in the ball's description of the geometry as abrupt points, barriers and singularities.

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1. ### I Rolling ball, change of direction

Say I have a magic way to exert lateral forces on a free-rolling ball on a plane, with no slipping. Say I apply a force for a given period from the South, the ball starts rolling to the North and attains a constant speed. Then I suddenly apply the same force for the same period but from the...
2. ### A rolling ball, find distance traveled

I figured the best way to do this is to focus on the second half of time. We can use the information there to find acceleration and that should make it fairly simple to find distance traveled in the first 5 seconds. Average speed in 5s-10s I found to be 40m/s. My problem is that to find the...
3. ### Free body diagram for an inverted pendulum in the rolling sphere

So, to obtain the motion equations I initially plotted the free-body diagram (see picture). Then I’ve tried to get equations, but I’m not sure, do I have done it rightl. I will be gratefull if someone could help me.
4. ### Speeds of the rolling ball at different points in this roller coaster track

For this question i tried to reason with my self that C was the fastest and A was the second fastest. B would be the third fastest and D would be the least fastest since the ball has to go up. I looked up the answer and it says that C is the fastest , B and D are equal, and A is the slowest. How...
5. ### Rolling ball inside a shell problem

I was able to solve this problem easily by using the fact that the center of mass of the system is stationary as ##\sum F_{ext} = 0## for the ball and shell system. since COM's of both objects can be replaced with point masses at there center, the shell will have maximum displacement when its...
6. ### 3d simulation of a rolling ball

How did you find PF?: Google Hi, I'm looking for advice on how to simulate a golf ball rolling on a green. The green will have been scanned using a 3d scanner by an Engineering Surveyor. I'm trying to model putting a golf ball from any position on the green, looking for a path line to the...
7. ### Smooth rolling ball rolls down hill, how far can it fly?

Figure of the problem. There are many exercises like these, and I've read the whole chapter and I got no clue where to start here. Kinetic energy from gravity is: E = mgh = 39.3m I could try change v to ωr in the K equation but it will leave me nowhere because I don't have the mass nor the...
8. ### A ball (sphere) rotating along a moving incline

Homework Statement We have a ball of mass ##m##and radius ##r##. it is placed on an incline (We don't know the angle of the incline, nor we do whether the angle is constant along the incline - maybe it is a curved incline) and then released. The COM of ball is ##h## meters above the incline at...
9. ### Height to which rolling ball rises on a surface

1. The problem A ball moves without sliding on a horizontal surface. It ascends a curved track upto height h and returns. Value of h is h1 for sufficient rough curved track to avoid sliding and is h2 for smooth curved track, then how are h1 and h2 related (greater, lesser, equal or multiplied by...
10. ### Find the force P such that the disk rolls without slip

Homework Statement When a disk rolls in a surface whitout slip, the velocity of the disk's edge (where it contacts the surface) is zero with respect the surface and the friction force is less than the maximum allowable of Us.N, where Us is the coefficient of static friction and N is the normal...
11. ### Finding the speed of rolling ball

Homework Statement Homework EquationsThe Attempt at a Solution In rolling motion, friction doesn't work. So, applying work energy theorem, ## \frac 1 2 m v_0 ^2 =\frac 1 2 mv^2 + \frac 1 2 I_{center} \omega ^2 ## ## taking~ I_{ center} = \frac 2 5 m R^2 ~and ~ v =\omega R , v = \sqrt {(...
12. ### Calculate angular velocity of a ball rolling down incline?

Homework Statement An 7.80-cm-diameter, 400 g solid sphere is released from rest at the top of a 1.70-m-long, 20.0 degree incline. It rolls, without slipping, to the bottom Homework Equations I=2/5 Mr^2 K = 1/2 m*v^2 Kroll = 1/2 Iw2 mgh=K+Kroll The Attempt at a Solution Using the above energy...
13. ### Rolling ball and generalized co-ordinates

Consider a sphere constrained to roll on a rough FLAT HORIZONTAL surface. A book on classical mechanics says it requires 5 generalized co-ordinates to specify sphere's configuration: 2 for its centre of mass and 3 for its orientation. I did not understand why 3 for orientation. I guess only 2...
14. ### What is the minimum height?

Homework Statement An empty ball , of mass m moment of inertia I = (2m.r²)/3, is rolling across the path shown below : there is friction fr from A to C . r is the radius of the ball , and R is the radius of the circular part within the path . what would be the minimal height h , so...
15. ### Collision of Rolling Ball and Cart

Say a ball rolls down to the right with slipping with on an arc incline so that at the bottom it leaves horizontally. The instant it leaves horizontally and is now on a cart with mass with frictional surface. So the ball will roll on the cart with kinetic friction pushing to the left altering...
16. ### Rolling ball goes through a loop-the-loop....

Homework Statement Hi everybody! Here is a classical mechanics problem about a ball (mass m, radius r) rolling down a slope (from height h) and going through a loop-the-loop. a) What is the minimum height h from which the ball must roll in order to successfully complete the loop-the-loop...
17. ### Ball rolling and slipping with backspin

Homework Statement A solid ball of mass M and radius R and moment of inertia I is placed onto a table with an initial velocity v_0 to the right and angular momentum w_0 anticlockwise (i.e the ball has backspin). Due to friction, the angular velocity and linear velocity changes as the ball both...
18. ### A rolling ball accelerating down an incline

Homework Statement source:http://www.wired.com/2014/07/a-rolling-object-accelerating-down-an-incline/ For a ball rolling on an incline, I know how to calculate the acceleration. However, I am quite confused about a situation. What if static friction acting on the ball is equal to the...
19. ### Friction Direction on Rolling Ball: Am I Missing Something?

My question is the following. A ball is initially skidding and eventually starts rolling on a flat plane with friction, and later comes to a halt. Which direction does friction act? (see diagram) If friction acts to the right, then the translational speed will go up, and that's not right...
20. ### Rolling ball in a enclosed cone problem

Hello , I am new here , and at start id like to say that i`m lousy at formulas and math :) . I've been searching and googled my problem and i couldn't find any solution to it . So here it is. Ball and a cone are rubber coated .Ball is rolling inside enclosed cone, when ball reaches speed it...
21. ### Rolling Ball and Proportionality Between Distance and Time

Homework Statement A ball starts from rest and rolls down a hill with uniform acceleration, traveling 130m during the second 6.0s of its motion. How far did it roll during the first 6.0s of motion?Homework Equations I guess: v=v(0)+at v^2=v(0)^2+2ay x=x(0)+v(0)t+0.5at^2The Attempt at a...
22. ### Rolling ball inside the cone

Help me to understand my physics homework Suppose if a ball is rolling down in an inclined plane, what happens to the normal force acting on it? How to understand the Normal force in this situation Please explain Thanks
23. ### Rolling Ball and angle of incline

Homework Statement A uniform solid sphere rolls down an incline without slipping. If the linear acceleration of the centre of mass of the sphere is 0.2g, then what is the angle the incline makes with the horizontal? Repeat for a thin spherical shell. Homework Equations \sum \tau = I \alpha...
24. ### How Does Slipping Affect the Acceleration of a Rolling Ball?

Homework Statement A rigid ball of mass m = 6kg and radius R = .23 m is sitting on a table. The mass center and geometric center of the ball coincide, but the radius of gyration about its mass center is k = .19 m. The ball is initially at rest. There is a coefficient of friction μ = .435...
25. ### If you kick a rolling ball perpendicularly, what happens?

Hey guys, I've been thinking about inertia/forces for a test I have soon and I've been stumped by a question that the teacher gave us a while ago. Suppose a football is rolling along the ground and you give it a swift kick in a direction perpendicular to its initial motion. In what direction...
26. ### Rolling ball and impulse (Too easy to be true?)

Homework Statement Homework Equations The Attempt at a Solution The change in velocity = a * change in ω I think that makes sense since for pure rolling v = aω 16 marks like that?
27. ### How Far Will a Rolling Ball Go?

If a ball is given a velocity, and left on horizontal rough floor then after what distance it will stop rollig (slippingis absent) ? Explain with force and torque acting on it .
28. ### Angular impulse of rolling ball

In the following, we have a sliding sphere, when it meets a floor with friction. I want to use the angular impulse method to find an expression of the v when pure rolling starts. [sorry I have no idea how to type in latex.] This is obviously incorrect. But I can't find out what's...
29. ### Question regarding a rolling ball

Hi, This has been bugging me for a little while now. Imagine a ball is rolling along on a rough surface without slipping. Under ideal conditions it will just continue rolling indefinitely right? However, if you were to draw a free body diagram the normal and gravitational force would...
30. ### Rolling ball for capacitive touchscreen

Greetings: I want to make a stylus for a capacitive touchscreen which has a rolling ball at the end - like a ballpoint pen. I would like to make it myself in order to get the right size, rather than try and modify existing styluses on the market. I would really appreciate any pointers as to...
31. ### Rolling ball down slope at specific time

Homework Statement A uniform solid ball rolls down a slope. If the ball has a diameter of .5m and a mass of .1 kg find the following: The equation which describes the velocity of the ball at any time, given that it starts from rest. Homework Equations I've tried using energy...
32. ### Rolling Ball Friction Calculation

Hi All, I have a question concerning a rolling ball on a metal track. Basically I am designing a rolling ball sculpture and want to lay a bunch of elevated track (2 wires) up and down and around turns. I know that as the ball is rolling it is losing speed from friction, so as the track...
33. ### Rolling Ball on a Horizontal Bar with Angular Velocity ω

bar (length L) is turned with angular velocity ω, on a horizontal level. Αt length of the bar, there is a ball (mass m) which rolls (We suppose that there is no friction force). The ball begins from constant utmost the bar with initial velocity u0. When the ball reaches in the L? Can you help...
34. ### Simple Harmonic Motion of a rolling ball

Homework Statement A ball rolls on a circular track of radius 0.61 m with a constant angular speed of 1.3 rad/s in the counterclockwise direction. A. If the angular position of the ball at t= 0 is \theta= 0, find the x component of the ball's position at the time 2.6 s. Let \theta= 0...
35. ### Exam Question: Rolling Ball on Concave Surface - Is Work Done?

Homework Statement A question I had in an exam today, just wanted to see whether it was right: A ball is rolling down the inside of a concave surface. The radius of the ball and the curvature of the surface is such that there is no slide. Is work done by a) the friction force b) the Normal...
36. ### Projectile motion of a rolling ball

Homework Statement a ball rolls off the top of a stairway with a horizontal velocity of magnitude 1.50m/s. The steps are 20cm high and 20 cm wide. Which step will the ball hit first?Homework Equations d = v1t + at^2 a = -9.8m/s^2 t= 2viSinθ/ 9.8 horizontal displacement = vi^2Sin2θ/ 9.8 The...
37. ### Solving for Time and Distance of a Rolling Ball

Homework Statement Chuck gives a horizontal speed v to a ball that then rolls off a lab bench y meters high. How long a time will it take the ball to reach the floor? How far from a point on the floor directlyt below the edge of the bench will the ball land? Calculate how long and how far...
38. ### Rolling ball Free fall question

Homework Statement A ball moving with constant speed 1.0 m/s on a horizontal table rolls off the edge of the table. The ball hits the floor 0.50 seconds after leaving the edge. Suppose you roll the same ball on the same table with constant speed 2.0 m/s. After leaving the edge of the table...
39. ### Rolling ball down a slope, how to find final velocity?

Homework Statement A ball is rolled down a rough hill with coefficient of \mu<tan\theta. The hill has a height of h. The ball has moment of inertia of I, mass of m, and radius of r, which are all constant. What is the final velocity of the ball at the bottom of the hill? P.S. I made this...
40. ### Solving for x-Displacement of a Rolling Ball on an Inclined Track

Homework Statement a track is inclined in such way that the velocity of the metal ball is 60 cm/s at 25 degree below the horizontal. mathematically determine the total x displacement of the metal ball. weight of ball: 65grams height from floor to the end of the track: 76.15cm velocity of the...
41. ### How Does a Rolling Sphere Overcome a Block Without Slipping?

A uniform solid sphere of radius R and massM rolls without slipping on a horizontal plane. The centre of mass of the sphere moves initially with velocity ~v directed perpendicularly to a fixed block of height h < R. The sphere hits the block and the collision is such that the point P on the...
42. ### Modeling Rolling Ball in x-y Plane

Hi All, I'm trying to figure out how to model a rolling ball in the x y plane. I've started with the basic equation of motion with constant acceleration d = v_{}0t + 1/2at^{}2 v_{}0 is the initial velocity a is acceleration t is time Assume that v is a vector at an angle \alpha...
43. ### Friction force on a rolling ball

Homework Statement A uniform hollow spherical ball of mass 1.75kg and radius 40.0cm rolls without slipping up a ramp that rises 30 degrees above the horizontal. The speed of the ball at the base of the ramp is 2.63m/s. while the ball is moving up the ramp, find the acceleration of its center...
44. ### What is the relationship between sliding and rolling motion of a ball?

hi there! I considered the following problem: a ball of radius R on a horizontal plain is at first in rest. Then it receives a horizontal force for a very short time at a point placed 1/3R from the plain and the ball starts moving with initial velocity v_0. There is also a friction when...
45. ### Rolling Ball Height In Terms of Ho

Homework Statement A basketball (which can be closely modeled as a hollow spherical shell) rolls down a mountainside into a valley and then up the opposite side, starting from rest at a height H0 above the bottom. In the figure, the rough part of the terrain prevents slipping while the...
46. ### Does a relativistic rolling ball wobble?

A spherical ball rolls without slipping along a surface, with uniform velocity v/c (close to 1) with respect to the lab frame. It is thus seen to contract by a factor of \gamma, forming a grape-like shape. Why doesn't it wobble as it rolls, like a rolling grape? One can certainly argue...
47. ### Solve Rolling Ball Problem: Find Speed & Normal Force

Hey there. I have a problem about rolling ball and it's from my homework. 1. Homework Statement A ball rolls down the surface of a rough fixed sphere of radius r, starting rest at the top. What's its speed when the line between the two centres makes an angle alpha with the upward...
48. I

### Rolling ball distance Math problem

I have this math problem for school that I need help with A ball is rolling down an inclined plane. The equation I have is y = .165x^2 + .997x + .845 where y is the distance traveled and x is the time taken I want to predict the distance it has rolled in 2 days, which I can do but what...
49. ### How far will a ball travel when rolled off a ramp?

Homework Statement Given the following variables find how far the ball will land away from the point it leaves the ramp to the point it hits the ground. Vertical: Delta X= 1m Velocity Final= ? Velocity Initial= ? Acceleration= -10 m/s^2 t= ? Horizontal: Delta X= ? <- Objective...