Rolling Definition and 1000 Threads

Consider a ball of radius r and total mass m, with a nonuniform but radially symmetric mass distribution inside it, so that it can have an almost arbitrary moment of inertia I. (a) If this ball is projected across a floor with an initial velocity v, and is at first purely sliding across the...

A bat lies along the x-axis so that the tip of its handle is located in (0, 0) while the other end is at (0.9 m; 0). The center of mass is at (0.6 m; 0). A ball hits the bat perpendicularly at (x, 0), causing an impulse I. The bat’s moment of inertia through the center of mass is J = 0.0530...

Let's tie a rope on an object, then we swing the object around in a circle, then we start running forwards while continuing the swinging. (All velocities are relativistic) An assistant takes lot of pictures of us doing this stunt. Then finally we study the pictures. We will notice that...

neglecting friction from the slope and air resistance, what are the possible forces acting on the ball? i can only think of 2: gravitational force by the Earth on the ball. normal force exerted by the slope on the ball. are there any other forces else that i missed out?

Hi guys, Homework Statement I'm trying to find the theoretical time it takes for a glue stick to roll down an inclined plane of 10 degrees. We then have to compare it to the practical value, which was 1.09 secs.(Average over 10 repetitions). The glue stick has a mass of 10g. The distance of...

Homework Statement A hoop of mass ##m## and radius ##a## rolls without slipping inside a pipe of radius ##R## (the motion is 2D). Write down the kinetic and potential energy. Hence find the frequency of small oscillations about equilibrium. Homework Equations Moment of inertia of a hoop...

Why roll an aircraft? If an aircraft can pitch and yaw, when does it need to roll? Thanks, Dirk

A ball is attached with a string on the side. When the string is pulled up, static friction accelerates the ball forward while the tension rotates the ball. When a ball is placed on a incline with friction, is kinetic friction opposing the motion and giving the ball torque while gravity...

Hi, The below questions are NOT HW questions, but I have a big exam coming and I would wholeheartedly appreciate some/any assistance with the following two issues, namely: (1) Direction of static friction in case of rolloing without slipping (2) Direction of α and VCM in case of rolling without...

It seems that I could have a solid cylinder roll down faster than a solid sphere if the center of the solid cylinder had a very dense material and then a less dense material towards the outside.

Imagine a set of train tracks. Now there is one bridge (a resistor) connecting the two rails in one spot. On a different spot, there is rolling axle that acts as another bridge and it makes good electrical connection with the rails creating a full rectangular circuit. This axle rolls at a...

Homework Statement Roll a 6-sided die 5 times. Event X is when a 1,2,3 shows up. Event Y is when 4,5 show up. Show the joint PMF. Homework Equations The Attempt at a Solution So... here is where I am at... X~Bin(5,0.5) & Y~Bin(5,1/3) P(X=x)=(5 C x)(.5^5) &...

Hello, My problem refers to hard tyres, so assuming none or very little lateral deflection. For a particular tyre on a particular floor there is a rolling resistance against the movement when the tyre is rolling. In a simplified case the resistance can be approximated as a rolling resistance...

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...

Hi everyone - quick question on something that's been bugging me. So, train wheels, which are solid steel, have incredibly low rolling resistance, an order of magnitude less than average car tires. This is because they don't bend significantly, so you're not wasting energy to heat as in the...

A bike rolling down a hill will on average stay upright for longer than a free standing bike? I can't think of a way to explain why this is?

Freight train is more efficient than truck due to lower rolling resistance. And I wonder which one has lower rolling resistance, small diameter or larger one or it doesn't not depend on diameter at all? Both are steel wheel on steel rail.

Five standard 6-sided dice are rolled. What is the probability that at least 3 of them show a six? I am surprised my answer is wrong. First the total outcomes are 6x6x6x6x6=7776 Successful outcomes 10x6x6=360 There are 10 ways to choose 3 from 5 and then the remaining 2 can be any number...

Homework Statement Homework Equations The Attempt at a Solution The force on the loop due to magnetic field in the direction normal to the incline is ##qvB##. Balancing forces in the direction normal to the incline, mg\cos\alpha=qvB+N where ##N## is the normal reaction due to incline and v is...

We know that in real world scenarios, for rolling without slipping of bodies like sphere, dis, cylinder etc. there is a rolling resistance present. This rolling resistance comes from the fact that in actual situations bodies aren't perfectly rigid. So there is some compression at the point of...

Is friction always zero when pure rolling has begun? Or is it static? Is there a difference between saying static friction at the point of contact and zero friction at the point of contact at the time when pure rolling has begun? That is of course for a rough surface on which the object is rolling.

Homework Statement A solid sphere of radius R is given a translation velocity vo on a rough surface of coefficient of kinetic friction=coefficient of static friction=μ. After what time does the sphere begin pure rolling? Also find the the angular velocity and linear velocity of the sphere at...

Why don't we consider radial acceleration on the lowermost point in rolling without slipping?

Homework Statement This is a conceptual doubt. "A sphere rolls without slipping moving with a constant speed on the fixed rough surface. Friction between the surface and the sphere is sufficient to prevent slipping." What does it mean that friction is enough to prevent slipping? From what...

Hi all, I have a question about how to analyze the problem of a ball rolling down an incline plane. Assuming there is friction, at each instant the ball swivels about a pivot point on the incline that is stationary due to static friction. We then would analyze the torques about this point...

Is frictional force necessary for rolling without slipping? If yes then does that mean that if we provide torque to a solid sphere on a frctionless surface will it nor rotate? I didn't understand that when does static frction arise and when does kinetic friction arise when a body is rolling...

What do we mean by the statement "Rolling with slipping"? I couldn't imagine this situation as a real life scenario.. I mean to say that if the body (say a solid sphere) is slipping/skidding then how can it rotate? If it will be rotating it won't be slipping/skidding. How can the two happen...

Hi all: I have been wondering: picture a cylinder sitting above a sheet of sand paper, assume static friction between the sheet of paper and the cylinder. if i start pulling the sheet of paper at velocity v along a direction of rolling (to the left), the moment caused by static...

This is probably a silly question, but I want to make sure I get it right for a story I'm writing. I want to roll an elongated spaceship "around" it's horizontal axis (as opposed to flipping it end over end). Is it equivalent to say "along" the horizontal axis? In this case, I'm assuming...

Homework Statement A cylinder rolls without slipping down a hill. It is released from height h. What is its speed when it come down? The cylinder mass may be completely concentrated on the radius R, which is the radius of the cylinder. http://i.imgur.com/Ge3x1nu.png The Attempt at a...

Homework Statement A round cone A of mass ##m## and half-angle ##\alpha## rolls uniformly and without slipping along a round conical surface B so that its apex O remains stationary. The centre of gravity of the cone A is at the same level as point O and at a distance ##\ell## from it. The...

Hi PF. I'm currently developing a 2D platform game that is significantly physics-based using the Box2D physics engine. However, one of my main problems right now is that the main "character" of my game is a ball and unfortunately, Box2D does not support rolling friction. The result is that...

Homework Statement Homework Equations Wnon-conservative forces = ΔEnergy The Attempt at a Solution I understand that I am to solve for the D in Wnon-conservative forces since I know the friction force. I am just having trouble understanding what the initial/final kinetic...

Homework Statement An experiment was done to test the validity of the equation a = 2/3 g sin∅ for a rolling cylinder. A hockey puck was rolled down a wooden ramp at 5 different inclination angles, and the time it took to roll down the length of the board was recorded. ∅ was found using...

Homework Statement A solid sphere rolling on a rough horizontal surface with a linear speed ##v## collides elastically with a fixed smooth, vertical wall. Find the speed of the sphere after it has started pure rolling in backward direction. Homework Equations The Attempt at a...

Homework Statement A certain die is weighted such that probabilities of showing a 1, 2, 3, 4, 5, and 6 are (6/34), (8/34), (5/34), (3/34), (8/34), and (4/34) A) If two such dice are thrown, and you are told that the sum of the two is 10 or larger. What is the probability that the...

Homework Statement A cylinder of radius r, mass m, and rotational inertia 1/2mr2 slides without rolling along a flat, frictionless surface with speed v0. At time t = 0 the object enters a region with friction (with coefficients μk and μs), as shown above. Initially the cylinder slips...

Homework Statement A solid disk of mass m and radius R rolls without slipping with a velocity v. Assuming it doesn't slip, how far vertically will it roll up an incline? Homework Equations I=0.5mr2 E=0.5Iω2 KE=0.5mv2 PE=mgh The Attempt at a Solution I'm thinking that we need to...

Homework Statement Homework Equations The Attempt at a Solution My answer is a because for ball B it loses kinetic energy when it drops into the dip and comes back up. I'm having a hard time picturing ball b when it goes down the dip.. does it drop down and then jumps up...

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...

Homework Statement The mass of the ball: 136 G Length of the slope that its sliding down: 132 Cm Angle of the slope that its sliding down: 11,5228 ° All I have to do, is to find the velocity, and the acceleration of the ball. Though my teacher has given us no time at all for this project...

Do either of these actions impact upon the elastic modulus? I can't think of any reason why they would, but just want to make sure. Thanks.

Homework Statement I have a question from my homework. My homework is completed, but I've been running some thought experiments lately and I wish to conceptually discuss this. The problem has to do with a hoop rolling down an inclined plane. I had to find the Normal Force using...

Here are the few equations i set up... which ultimately led to a wrong answer. (In my solution, subscripts A refers to the ramp, B refers to the rolling pipe) ---------- I have a feeling that the acceleration if pipe A isn't simply downwards at 30deg. Cos the ramp is rolling away, so...

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?

Homework Statement A ball of radius ro rolls on the inside of a track of radius Ro. If the ball starts from rest at the vertical edge of the track, what will be its speed when it reaches the lowest point of the track, rolling without slipping? Included below is a link to the diagram...

I've been having trouble with this topic for a while now. I've re-read the section dozens of times now, but I'm still not exactly clear and I was hoping for clarification on a couple of things. In a system of particles, I can see intuitively how the velocity of a particular particle will be the...

Homework Statement A spherical ball of mass m and radius r rolls without slipping on a rough concave surface of large radius R .It makes small oscillations about the lowest point.Find the time period. Ans : 2∏\sqrt\frac{7(R-r)}{5g} Homework Equations The Attempt at a Solution...

[FONT=Verdana]Hi, I'm trying to find the Acceleration of a ball rolling down on a parabola. [FONT=Verdana]If I could find it, then I could integrate it twice and find it's parametric equation given by the time. [FONT=Verdana]How could I find this? [FONT=Verdana]I tried a few things, but...

Homework Statement I have math experiment where I roll a pair of honest dice 20 times. The results are: 2,3,4,4,5,5,6,6,6,7,7,7,7,7,9,9,9,10,10,11 write a frequency table of the outcome of the dice roll with respect to size: 2,3,4,5,6,7,8,9,10,11,12 Firstly there must 36...