Rolling Definition and 1000 Threads

Homework Statement Two dice are rolled: what is the probability of rolling a 10 and an 11 before rolling a 7?Homework Equations The Attempt at a Solution Is conditional probability the way to go here? Let, A= rolling 10 B= rolling 11 C= not rolling 7 P( A and B| C)=P(A and B and C)/P(C)...

Does friction does any work on an object purely rolling? Would mechanical energy be always conserved when when an object rolls? I feel that friction does no work as the point of contact never moves. So there will be no change in energy. Am I having conceptual error?

1. Homework Statement A cylindrical hoop rests on a rough uniform incline. It is released and rolls without slipping through a vertical distance h0. It then continues up a perfectly smooth incline. What height does it reach? 2. Homework Equations GPE=mgh Rotational Ke =0.5Iw2...

Hello, I need to apply rolling friction to a ball, but I don't understand where to plug it in. I know the rolling friction that I want to put in, but I can't just subtract the force of rolling friction on velocity, because the ball would never come to a stop, it would turn back again (and make...

Homework Statement The Attempt at a Solution The sphere is rolling without sipping, so the lowermost point has 0 velocity ... so why would there be any friction? I know that if there will be no friction .. sphere will just slide down and not roll but still as i said ... why will...

Hello people, I have 2 scenario's. One is a ball rolling down a ramp with friction, onto pavement with friction. The other is a ball rolling down a ramp without friction, onto pavement with friction. Everything between them is the same except for the friction. I think that having no...

Homework Statement The Attempt at a Solution In rolling without slipping, the friction does some work of torque about the axis of rotation. So mechanical energy is not conserved. A) - r),t) B) and C) - r),t) D) - One example I can think for the instant centre of rotation is...

Hi folks, I'm imagining the following situation: Two balls lie at the base of a hill, side by side, not touching. One is larger and masses more than the other. They are made from the same material. Suddenly, they both experience the same acceleration towards the hill. They don't ever come...

Homework Statement A hollow basketball rolls down a 30\circ incline. If it starts from rest, what is its speed after it's gone 8.4 m along the incline? Homework Equations v=\omegaR The Attempt at a Solution I don't really know where to start with this. I've done similar problems, but I was...

Well, it's my second post about rigid body. I originally posted this on introductory physics, but as nobody answered this, or the previous topic, I've decided to post this here. Homework Statement I have this other exercise rigid in the plane, with which I am having problems. The rod of...

Homework Statement I have this other exercise rigid in the plane, with which I am having problems. The rod of mass m and length l, is released based on the vertical position of rest with the small roller end A resting on the slope. Determine the initial acceleration A. (neglect friction and...

hi , I am going to design sealpress mechanism for rotary system . I need to find out how much torque required to rotate my steel roller which is connected to end of my cylinder. from wikipedia i find out rolling resistance = The force of rolling resistance, not adjusted for...

Hello i am having trouble understanding what would be the angular and linear velocity of the center of mass of a rod that falls of a step and hits the ground and continues rolling. I know that mechanical energy is not conserved after the rod hits the ground, as that would be an inelastic...

Homework Statement A toy train rolls around a horizontal 1.8 m diameter track. The coefficient of rolling friction is 0.11. What is the magnitude of the train's angular acceleration after it is released? How long does it take the train to stop if it's released with an angular speed of 31 ...

Hello everybody, I am having a hard time understanding a very simple principle involving a rolling wheel. I know that the velocity at the bottom "contact point" of a rolling wheel is zero relative to a stationary observer.. yet I don't see how this is true. So I made a quick sketch and here is...

Hello, I am designing a rig to measure the rolling moment of a model aircraft. The rig will have a settable yaw, pitch and roll, but only the rolling moment is to be measured. The model aircraft will be similar to an Airfix model. Approx dimensions: L221 x W152. I was just wondering if anyone...

Friction is necessary to make motion rolling but if the body is already in rolling motion on rough surface without slipping then, is friction necessary to continue the rolling motion ?

Homework Statement http://img406.imageshack.us/img406/9971/setupq.jpg In the diagram, there is a rope wrapped around a cylinder which is connected to a mass m. The cylinder is on cart, so the cart accelerates to the right at a value of a. The Attempt at a Solution so far I got this: lets say...

When, let's say, a cylinder is rolling on a plane, and there is a rope coiled around the cylinder and the rope moves at an acceleration of A(rope) at the upper part of the cylinder to the right. Ok, so when I try to envision it, the cylinder is rolling in the CW direction. so R(alpha)= -...

Homework Statement What is the value of the rolling friction force given 1)Fnet=0.24N (deceleration up the ramp) and 2)Fnet=0.21N (acceleration down the ramp)? Homework Equations Fnet = Fgravity - Ffriction (?) The Attempt at a Solution Somehow I need to combine these values to...

Homework Statement Block A starts from rest and slides 8m down a frictionless 30 degree angled inclined plane. It then crosses a 4m horizontal surface where the coefficient of kinetic friction is 0.2. What is the velocity of Block A after it has finished crossing the horizontal surface...

A car rolling down a hill with an inclination \alpha with the horizon experiences an acceleration a = gsin(\alpha) along the surface of the hill. Here g = 9.81 m/s^2. The car is released from rest at the time t0 = 0s a) Find the position s and the velocity v of the car along the hill after a...

Hi, I am a bit stuck. I am trying to work out the top speed a motorbike can reach, I have a table with bhp and torque and the highest bhp of 150 is at 9,000 rpm. I have done the following calculations: Diameter of tyre + wheel: 0.5m Circumfrence of tyre + wheel: 1.5707963m (round up to 1.6m)...

Homework Statement Drag=m(Mu*g+(V^2)/L) L=constant with unit of length initialV=V_0 how far the car will coast under this condition with initial V how long does it take to stop Homework Equations a=V*dv/dt The Attempt at a Solution there are linear and non-linear parts in this...

Homework Statement So a tire rolls with radius r. The CM of the wheel travels at a velocity of vcom. What is the acceleration of the top of the wheel and the bottom of the wheel relative to a passenger in the car and to a street sign on the street? Homework Equations a = v^2/r The...

Homework Statement A very small steel marble is shown rolling at a constant speed on a horizontal table. The marble leaves the table at M, falls, and hits the ground at P. This is illustrated in the diagram below which is drawn to scale. Calculate the time it took the marble to travel from L...

Homework Statement Disk a and b are identical and roll across a floor with equal speeds. Disk a rolls up an incline, reaching a max height h, and disk B moves up an incline that is identical except that it is frctionless. Is the max height reached by disk b greater than, less than, or equal to...

Homework Statement The center of mass (C) of the circular rolling disc is offset from its centroid (O) by an eccentric distance OC = \epsilon. The radius of the wheel is R. The disc is rolling without slipping at a constant rotational speed \omega by a variable torque T. Solve for this...

I have looked around several internet Physics sites and information sources, and even asked questions here and in other places, and can't seem to find answers to my questions about a thought experiment I came up with: Think about three similar cases: A ball, a solid cylinder, and a hollow...

Hi, I'm trying to model a wheel that is placed on top of a moving platform. The problem is that I'm running into a situation that seems very counter intuitive. I'm not sure if its a problem with my model or not. I've attached a picture that demonstrates the problem. To begin, neither the...

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...

hi ,this is my first post (and its not HW) i currently study dynamics of rigid bodies using (Hibbeler) and there's one thing about this type of motion (rolling) that just seems to elude me for any planar motion we have 3 equations \Sigma F_{{x}}={\it ma}_{{g_{{x}}}} \Sigma F_{{y}}={\it...

Homework Statement A solid wheel of mass M and radius R rolls without slipping at a constant velocity v until it collides inelastically with a step of height h < R. Assume that there is no slipping at the point of impact. What is the minimum velocity v in terms of h and R needed for the...

Homework Statement An 8 cm, 400 g sphere is released from rest at the top of a 2.1 m long, 25 degrees incline. It rolls, without slipping, to the bottom. a. What is the sphere's angular velocity at the bottom of the incline? b. What fraction of its kinetic energy is rotational? Homework...

This should be a pretty simple question for someone out there, If you have a ramp with the same height, and the same angle, and you take two spheres of different size, but identical materials, and you rolled them down this incline. Which would reach the bottom first if rolling friction is...

Homework Statement A ball is rolling off an inclined plane. After 1 second the ball has traveled 10cm. How far will it travel in 3 seconds?Homework Equations v = l/t v = v0t + at x = x0 + v0t + at2/2 The Attempt at a Solution v = l/t1 v = v0t + at (there's no starting velocity, so) l/t1 =...

Homework Statement Consider a solid disc (cylinder) with mass M and radius R initially rotates with an angular velocity \omega. Then it is slowly lowered to a horizontal surface with coefficient of kinetic friction, \mu. What is the distance of the disc traveled before it starts to roll...

Homework Statement A cylinder of mass m and radius R rolls without slipping down a wedge of mass M. The wedge slides on a frictionless horizontal surface. The angle between the wedge's hypotenuse & longest leg (which lies on the frictionless ground) is beta. The wedge's hypotenuse DOES have...

Hi All, I was wondering if anyone could give me a suggestion to solve this "With one die, suppose in a round, you earn the amount of dollars equal to the value of the upwards face of the die. (eg. you earn $6 if you roll a six.) Now also suppose after your first roll, you are given the...

Hi, I have a question about one of my project involved 2electrical motors that I have to size to accelerate a Robot on robber wheels. there are a lot of confusing stuff in the internet that make me give up.:( so here it is: the weight of Robot is 10 kg, standing on two legs that has 2 robber...

Homework Statement A ball of mass M and radius R initially slides with speed vo but without rotating on a horizontal surface with friction. Without knowing anything about the nature of the frictional force, find the speed of the ball when it begins to roll without slipping. Homework Equations...

Homework Statement [PLAIN]http://img87.imageshack.us/img87/9964/impactforceonbike.png A roller is rolling with a constant speed before and after the drop. How do i figure out the impact force exerted on the wheel when it just touch the floor from a height h? Assume, angular velocity...

Hi guys, I have a very simple but confusing problem that I have with die. It's not a homework problem, more a general understanding question. Now, question (im my own words) Four six-sided die are rolled together and independently to each other. Is the chance to roll a sum of (even) or (odd)...

A cylinder of a mass M and a radius R starts at the top of a hill at a height h, and rolls to the bottom. At the bottom of the hill, what is its linear velocity, linear momentum, and angular momentum? I believe the the velocity is sqrt((4/3)gh) and the the angular momentum is mvsin(theta)...

Homework Statement A tire is rolling along a road, without slipping, with a velocity v. A piece of tape is attached to the tire. When the tape is opposite the road (at the top of the tire), it's velocity with respect to the road is The Attempt at a Solution I have no idea where to...

Homework Statement After fixing your bicycle, you go for a ride on it along the path by the Charles River. At all times, your wheels roll without slipping. At a particular instant, you are traveling in a straight line with a speed of v. I can't figure out part B Homework Equations part A...

Hi guys. I had a l'll confusion regarding rolling. Suppose you have a wheel and we set it into motion. If we give it more torque than required to just start rolling it'll accelerate..right? But will it slip greatly if we supply more torque? Thanks in Advance.

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...

We've just studied rolling without slipping and I was having some trouble deciding the direction of the frictional force in some cases. So I pondered a little bit and recalled how you choose the direction of friction for "normal" translation without rotation: If the friction is static, then...

1. A 2000 kg car in neutral at the top of a 20 degree inclined 20 meter long driveway slips its parking break and rolls downward. at what speed will it hit the garage door at the bottom of the incline? Neglect all retarding forces Homework Equations The Attempt at a Solution