Rolling is a type of motion that combines rotation (commonly, of an axially symmetric object) and translation of that object with respect to a surface (either one or the other moves), such that, if ideal conditions exist, the two are in contact with each other without sliding.
Rolling where there is no sliding is referred to as pure rolling. By definition, there is no sliding when there is a frame of reference in which all points of contact on the rolling object have the same velocity as their counterparts on the surface on which the object rolls; in particular, for a frame of reference in which the rolling plane is at rest (see animation), the instantaneous velocity of all the points of contact (e.g., a generating line segment of a cylinder) of the rolling object is zero.
In practice, due to small deformations near the contact area, some sliding and energy dissipation occurs. Nevertheless, the resulting rolling resistance is much lower than sliding friction, and thus, rolling objects, typically require much less energy to be moved than sliding ones. As a result, such objects will more easily move, if they experience a force with a component along the surface, for instance gravity on a tilted surface, wind, pushing, pulling, or torque from an engine. Unlike cylindrical axially symmetric objects, the rolling motion of a cone is such that while rolling on a flat surface, its center of gravity performs a circular motion, rather than a linear motion. Rolling objects are not necessarily axially-symmetrical. Two well known non-axially-symmetrical rollers are the Reuleaux triangle and the Meissner bodies. The oloid and the sphericon are members of a special family of developable rollers that develop their entire surface when rolling down a flat plane. Objects with corners, such as dice, roll by successive rotations about the edge or corner which is in contact with the surface. The construction of a specific surface allows even a perfect square wheel to roll with its centroid at constant height above a reference plane.
I've been arguing with my physics teacher about why the deacceleration of a person on a skateboard or bicycle that is gliding along the ground (without pedaling or pushing) is dependent on the mass of the person riding it (The higher mass person goes further). I say that it is solely due to...
Hey all,
I'm stuck on this problem and not sure how to proceed/if I'm in the right direction.
Problem: One reference frame N sits at the origin (inertial frame) while another frame, B, describes a disk rolling on a circular ring about the other frame. Picture below
(A) find the direction...
Homework Statement
I'm doing a coursework where I must find the angular acceleration of a rolling tin can using theoretical values. I have its mass and radius. I actually have experimental data so i have access to the actual values of angular velocity and angular acceleration, as well as time...
Homework Statement
A force(Fi) is acting on the top point of a disc of radius r and mass m. The disc is rolling without slipping. Angular velocity of disc after center has been displaced distance x is?[/B]Homework Equations
Energy conservation; Moment of inertia of disc (MR^2)/2
The Attempt...
Hi I am doing an assignment where I roll a tin can filled with car oil. This will affect its rolling because it distorts its centre of mass, resulting in an awkward rolling motion. I have already done the experiment, the first revolution is the slowest one by a lot because it slows down a lot...
Greetings, mechanical engineers of Physicsforums,
I have been struggling with a particular problem calculating an ideal motor RPM for economical highway cruising.
The motor I am looking at is the Subaru EE20 Diesel motor. Its torque curve can be found here...
Homework Statement
Two cans of the same size, mass, and shape are released from a ramp at the same height. One of the cans has milk and the other has refried beans. Which will reach the bottom first?
Homework Equations
Ktotal = Ktranslation + Krotational
The Attempt at a Solution
Since they...
Homework Statement
Two solid cylinders are placed on an inclined plane with inclined angle Θ. Both mass of cylinders are m, but the radius bigger cylinder is two times the radius of small cylinder. A string links the big cylinder's center to small cylinder's top (see picture). Both cylinders...
when a sphere starts moving with initial velocity ##v_0## and zero angular velocity in a plane surface having friction, then first it will start rotating till it starts pure rolling. that is, its velocity of centre of mass will decrease due to backward friction and angular velocity will increase...
Homework Statement
A uniform sphere with know mass m, moment of inertia I, and radius Rs is traveling through free space with initial horizontal linear velocity v1 and rotational velocity w1. It then makes tangential contact with a horizontal surface and instantaneously starts rolling without...
Homework Statement
A solid cylinder (I = 1/2 mr^2) is being pulled by a force applied at 40 degrees above the horizontal to the axle and directed through the center of the roller. Roller moves across a flat, horizontal surface. Cylinder has radius of 0.60 m, and mass of 250 kg. Assume roller...
Homework Statement
A bowling ball rolls without slipping up a ramp that slopes upward at an angle β to the horizontal. Treat the ball as a uniform solid sphere, ignoring the finger holes. Explain why the friction force must be directed uphill.
Homework Equations
F=ma, torque=I(alpha)...
Homework Statement
A 1 kg ball with a radius of 20 cm rolls down a 5 m high inclined plane. Its speed at the bottom is 8 m/s. How many revolutions per second is the ball making when at the bottom of the plane?
Homework Equations
circumference = 2πr
velocity = distance / time = circumference /...
How does one calculate the probability of a sum of r in the dice rolls of n dice? Can a probability distribution be written for something like this, to calculate the probability of a sum greater than r, greater than or equal to r, equal to r, less than or equal to r, less than r, etc.?
I do not...
Homework Statement
We have experimented on rolling cylinders and have gotten the function for a rolling cylinder but have gotten a strange constant from experiment.
Homework Equations
t = 2\sqrt{\frac{l}{g}(1+\frac{r}{R})\frac{1}{\sin{\theta}}}-0.5
The Attempt at a Solution
Is this constant...
Homework Statement
Material is blown into cart A from cart B at a rate b kilograms per
second. The material leaves the chute vertically down-
ward, so that it has the same horizontal velocity u as cart B. At the
moment of interest, cart A has mass M and velocity v. Find dv/dt,
the instantaneous...
Homework Statement
A yo-yo is pulled with a constant tension T. The string is horizontal and parallel to the table and unwinding from the bottom of the spool, as shown. The yo-yo's outer radius is R and the spool radius is r. The mass of the yo-yo is m and the moment of inertia of the yo-yo...
Homework Statement
Which statement concerning a wheel undergoing rolling motion is true
(a) The angular acceleration of the wheel must be zero m/s2.
(b) The tangential velocity is the same for all points on the wheel.
(c) The linear velocity for all points on the rim of the wheel is non-zero...
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...
I don't really have a specific problem, but for example, I was doing a problem where a constant force unwounds a spool of wire (a disk). The force pulls at the top of the disk to the right and the force of static friction is also at the bottom to the right, the same direction as the sphere is...
How does friction affect the type of rolling motion of an object. For instance, does having more friction than the required friction for rolling cause the object to spin?
Consider this: We have a sphere rolling down a slant, released from some height h with null velocity. At the end of the slant its potential energy will have been fully converted to kinetic energy, part translational and part rotational.
Now consider this: at the end of the slant the ball enters...
Hi everybody, I know this problem has been posted before, but it envolved Lagrangian methods which I haven't seen yet. I would appreciate any help.
1. Homework Statement
A small hoop is rolling without slipping on a bigger cylinder which is stationary. I need to write Newton's Laws and...
You have to apply a force to counter the force of friction. In order to move fast the friction has to be reduced. So we have the invention of wheels. Rolling friction is much less than sliding friction. Experience shows that much less force is required to roll an object than to slide or drag it...
I would appreciate some help on this question involving a cylinder rolling down a slope; I'm far from comfortable with the physics involved.
Question here:
This is my free-body diagram of the forces acting on the cylinder:
Expressions for the acceleration in the x- and y-directions in...
A tundra buggy, which is a bus fitted with oversized wheels, is stuck in Churchill, Manitoba, on slippery ice. The wheel radius is 0.84 m. The speedometer goes from 0 to 27 km/h while the buggy moves a total distance of 7.0 m in 9.0 s.
Find the magnitude of the total acceleration of a point at...
Homework Statement
A uniform solid sphere, of radius 0.20 m, rolls without slipping 6.0 m down a ramp that is inclined at 28° with the horizontal. What is the angular speed of the sphere at the bottom of the slope if it starts from rest?
Homework Equations
KE=1/2Iw^2
PE=mgh
I don't know what...
Hi everyone, this problem involves smooth rolling and translational motion:
1. Homework Statement
A bowler throws a bowling ball of radius R= 11 cm along a lane. The ball slides on the lane with initial speed vcom = 8.5 m/s and initial angular speed w0 = 0. The coefficient of kinetic friction...
Hi everyone, I've been working on this problem for a while now, and I was hoping someone here could point me in the right direction. Here goes:
1. Homework Statement
A solid brass ball of mass 0.280 g will roll smoothly along a loop-the-loop track when released from rest along the straight...
Hey PF readers,
I am currently in dire need of a good(awesome) book on rotational and/or rolling motion which explains ALL the concepts and nicks of rolling and rotational motion. The book need not have many questions to practice bit should have HUGE amount of theory, that is, concept. It would...
Homework Statement
Two bicycle tires are set rolling with the same initial speed of 3.30m/s along a long, straight road, and the distance each travels before its speed is reduced by half is measured. One tire is inflated to a pressure of 40 psi and goes a distance of 17.3m ; the other is at 105...
Homework Statement
The flag is d=2mm thick and D=30 m long. We roll the flag and stick the short side of the flag (long side is 30m, short side's length is not given) on the ceiling so that the flag unwraps back to the ground. Flag is M=30kg.
1. Find the time it takes to 10 m of the flag to get...
A couple friends and I were brainstorming an idea today and thought of a way to make a pump using the waves in the ocean for enrgy.
So what it comes down to is say a 6cm i diameter steel ball in a tube, each side of the tube could have "pillows" that are part of a "membrane-pump". When the...
Hello everyone,
I cannot understand the logic behind determining the directions in the rolling problems. In all examples I have seen has a logic. Let us assume a rolling cylinder is moving to right as accelerating. If the cause of the acceleration is a torque the direction of the friction force...
Homework Statement
A uniform wheel of mass 10.0kg and radius 0.400m is mounted rigidly on a massless axle through its centre. The radius of the axle is 0.200m, and the rotational inertia of the wheel-axle combination about its central axis is 0.600kg.m2. The wheel is initially at rest at the...
Homework Statement
A constant horizontal force Fapp of magnitude 10N is applied to a wheel of mass 10 kg and radius 0.30m. The wheel rolls smoothly on the horizontal surface, and the acceleration of its centre of mass has magnitude 0.60m/s2. In unit vector notation, what is the frictional force...
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...
Homework Statement
Hi all, in my grade 11 book there is a question, and the question is :- there is a ball rolling on a chair by a speed of 5.0 m/s on the X axis, the ball hit the ground on a distance of 0.25 m on the X axis, What is the Δy and what is the speed on Y axis
ϑx (speed on X axis)...
I ran into this problem, and would like to see if there is something more elegant.
Suppose we have a sequence $a_1, a_2, \dotsc, a_n, \dotsc$ where $a_k$
is the (running) sum of rolling a standard 6-side die $k$ times.
E.g. What's the chance of saying the number $2$ appears in this sequence...
A hollow sphere with mass $$M$$ , radius $$R$$ , and moment of inertia $$I=2/3MR^2$$ about its center rolls without slipping with a initial center of mass speed $$v$$ towards a fixed ramp. It then rolls without slipping up the ramp. The ramp forms an angle $$\theta$$ with the horizontal...
[>A heavy sphere of radius r = 1.00 meter is fixed with respect to the ground. A small uniform solid sphere is placed at the top of the larger sphere. After a slight disturbance, the smaller sphere begins to roll downward without slipping. How high h is the small sphere above the ground at the...
Homework Statement
In this problem, we will demonstrate the Central Limit Theorem by a virtual test that involves
rolling of dice. To this end, you will create a function, with the following declaration line
function [avgDice, histDice] = rollDice(NumDice, NumRolls)
##\bullet## NumDice: the...
I have 3 fair dices. The probability of 2 of them lying in the same number without the 3rd doing so is given by \frac{N (N-1)}{N^3}, with N=6 in a regular dice.
What if I roll the 3rd dice twice as fast (i.e. 2 times for every time I roll the other dices)? Or three times as fast? Simple...
Definition/Summary
"Rolling" means moving along a surface without sliding.
The (instantaneous) point of contact is stationary relative to the surface. In other words: it is the instantaneous centre of rotation (if that surface is stationary).
Friction at the point of contact of a...
Homework Statement
A hoop sits on a bus. The bus begins to accelerate toward the right with acceleration a1, shown below. The bus tires do not slip on the road. As the bus accelerates, the hoop begins to roll without slipping on the rigid floor of the bus and has rightward center of mass...
I want to describe the motion of a ball that rolls without slipping in a plane where acts a force field not in the direction of the motion. To illustrate better, the ball is put on the origin, there is a field h in y direction, and a velocity v0 in the x direction. There is also a friction force...
Homework Statement
A child's hoop of mass M and radius b rolls in a straight line with velocity v. Its top is given a light tap with a stick at right angles to the direction of motion. The Impulse of the blow is I.
a. Show that this results in a deflection of the line of rolling by angle...
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 ...
suppose you had a ball rolling down a ramp, without slipping and compare it to a ball that starts with a velocity u that is horizontally to the side. how would the time taken be different to reach the bottom?
I have a concept about rolling friction which someone might be able to confirm for me. Let's say there is a steel ball rolling on a steel surface. It seems to me that the rolling friction force would be proportional to the rolling object's velocity.
My understanding is rolling friction is...