Rotational Definition and 1000 Threads

A car is moving foreword with a constant acceleration. I know the point of the tire in contact with the ground has a velocity of 0 (relative to the ground). Is the tangential acceleration at this point also zero? I came across an example problem in my text where this occurs and and it does not...

Homework Statement Starting from rest, a basketball rolls from the top of a hill to the bottom, reaching a translational speed of 6.12 m/s. Ignore frictional losses. Homework Equations (a) What is the height of the hill? (b) Released from rest at the same height, a can of frozen...

Homework Statement A small compass needle is situated in a uniform magnetic field. When displaced from its stable equilibrium position through a small angle and then released, it oscillates with a frequency of 5 Hz. A millijoule of work is needed to twist the compass needle round through...

Homework Statement A slender rod shown in the figure has a mass m and length l and is released from rest when theta=0 degrees. The horizontal and vertical components of force which the pin at A exerts on the rod at the instant shown in the figure is ? The Attempt at a Solution I have some...

Homework Statement A thin uniform-density rod whose mass is 3.8 kg and whose length is 3.0 m rotates around an axis perpendicular to the rod, with angular speed 34 radians/s. Its center moves with a speed of 10 m/s. (a) What is its rotational kinetic energy? (b) What is its total kinetic...

Hi everyone! I wanted to know if there is a possible way for a human-being to create a rotational motion of water in a metallic box by himself, probably using his own electric field (is there such a thing?) with no other accessories? It might be related to the term "Electric people"...

Rotational mechanics... Homework Statement This is actually a simple harmonic motion question but the doubt i have is with a concept in rotation... I will state the exact problem... A solid sphere(radius R) rolls without slipping in a cylindrical trough(Radius 5R). Find the time period of...

I've just watched this vid about rotations and torque: http://ocw.mit.edu/courses/physics/8-01-physics-i-classical-mechanics-fall-1999/video-lectures/lecture-21/ and they say that if u hit or pull something for a corner for example.. it will have the same speed like if u hit it in center...

Homework Statement A spherical body is rolling on a rough surface. then "the frictional force may or may not be zero" Is this statement is correct or not? we discussed about this in classroom. Some were saying it must not be zero and others were saying it may be zero. Which is correct?

Hey I'm making some kind of simulation... (in game maker) Ball collisions, ball to wall(friction)etc. So I'm asking: how do i calculate rotational speed if i know r, mass, and distance to where is force being applyed? I know that moment of inertia for a ball is 2/3*m*r2 and have no idea...

See the attached PDF document, all information is given and the help I need is on number 2-5, which is all one problem. I do already know that you have to do 2, then 5, then 3, then 4. Between 30 of my friends and I, we cannot get it. Thanks in advance.

Hi all; I'm building a mechanism that will raise and lower a small platform but I need to determine how much force is needed. Sadly, until the platform is built and set up I won't know how heavy it will be so I'm trying to just determine how to calculate the force various motors can put out so I...

Homework Statement There is a record spinning when a blob of putty falls vertically on its edge; which is .10m from the center. What is the rotational speed of the record after the blob sticks on it? additional information: mass of blob = .040kg mass of record = .10kg rotational inertia of...

Rotational Accel/Radians <<Solved>> Homework Statement Question 1) 18. Convert the following measurements to radians. c) the motion of an hour hand in 4.4 h = 2.3 Rad d) Earth’s rotation in 28.5 h = 7.5 Rad <<<<<<figured it out, thanks SammyS for that obivious yet overlooked detail...

Homework Statement Estimate the total rotational moment of inertia in Kg*m^2, of all the motors and generators in the Eastern United States. Homework Equations No other information was provided. The Attempt at a Solution First off I went to the following website to estimate the...

Homework Statement What is the rotational kinetic energy of Jupiter? Assume Jupiter is a uniform sphere with a rotational period of 9.81 hr. Homework Equations I= 2mr^2/5 Krot= I*omega^2/2 omega= 2pi/T The Attempt at a Solution i found the omega using the equation above and the...

Technically this is a homework question because it's from an assignment I'm doing as practice for my exam tomorrow. Imagine a rod standing on a table, the base of the rod is attached to the table with a hinge, so that the rod is able to swing between standing position and parallel with the...

Homework Statement Two rings of masses 'm' (smaller one) and '4m' (bigger one) are placed in the set up as shown in the diagram. The smaller ring is hung through a horizontal frictionless thread. The bigger ring is joined to the smaller ring in such a way that it can rotate freely about the...

Homework Statement Two rings of masses 'm' (smaller one) and '4m' (bigger one) are placed in the set up as shown in the diagram. The smaller ring is hung through a horizontal frictionless thread. The bigger ring is joined to the smaller ring in such a way that it can rotate freely about the...

Homework Statement An inelastic uniform sphere of radius 'a' is sliding without rotation on a smooth horizontal plane when it impinges on a thin horizontal rod at right angles to its direction of motion and at a height 'b' from the plane. Find the maximum velocity so that it will just roll...

1. A space station in the form of a large wheel, 124 m in diamete, rotates to provide and "artificial gravity" of 9.3 m/s^2 for people located on the outer rim. Find the rotational frequency of the wheel that will produce this effect. (answer in units of rpm) 2. v^2=gr, w=v/r, w/2pi =...

In a class demonstration, a bicycle wheel was held on an axle and spun. The result came to be that the wheel while rotating held a vertical position while holding it by a string attached to the end of the axle. After the wheel stopped rotating its vertical position ceased and the wheel attained...

Homework Statement The figure shows a view from above of two objects attached to the end of a rigid massless rod at rest on a frictionless table. Imagine a vertical rod, on the top end is a mass of m, an the bottom is a mass of 2m. The length of the rod is L and L/4 down from m (at top), a...

MMX proves light is isotropic in all directions. Hand held GPS units apply the Earth rotational sagnac correction which means light is not isotropic in all directions at the unit from the satellites. If a hand held GPS unit is placed at the same location as an MMX experiment, one...

I need some help with physics...Honestly, I'm a bit slow in the class and it's killing my GPA How do I calculate torque and normal force? I'm working on a lab. Basically, I'm balancing a meter stick with two different mass on both sides sides with a fulcrum in between them. I need to...

we have many accelerations in rotational motion ,and I don't know the difference between them. first the linear acceleration which as I understand is the vector acceleration which has the same direction as the change of velocity and it affects the speed and direction then it's two components are...

Homework Statement This is a question from the 1999 AP Physics C test. You can view the picture here, on Page 6: http://vhphysics.com/ap/x-test-q/Resource/b)%20Physics%20C%20Materials%20(656)/c)%20AP%20C%20Free-Response%20Problems%20(213)/Physics%20C%201999%20Free%20Response.PDF As...

Homework Statement Two spherical bodies with equal mass m1=m2=1000 kg are orbiting around a common barycenter in a weightless environment because of the gravitational attraction. A: Show how the frequency of orbiting is related to the distance between two bodies. B: We connect two...

I have 2 advantages of using rotational and orbital velocity of Earth in assisting easier rocket travel... 1. Uses less fuel as the rotational speed contributes to the rocket 2. Assists the rocket to easily produce the necessary escape velocity Are there anymore adv? I can't seem to...

Homework Statement A 16.0 kg bucket of water of is suspended by a rope wrapped around a pulley, which is just a solid cylinder 0.300 m in diameter with mass 12.0 kg. The cylinder is pivoted on a frictionless axle through its center. The bucket is released from rest at the top of a well and...

Homework Statement A solid sphere of mass m and radius r rolls without slipping along the track shown below. It starts from rest with the lowest point of the sphere at height h above the bottom of the loop of radius R, much larger than r. (Consider up and to the right to be the positive...

Homework Statement Given the following Rdisk = 2.50 cm, Raxle = 0.250 cm, Mdisk - 25.0g, Maxle = 0.750g a. Determine the rotational inertia of a yo-yo about it's center. b. Dervie using force and torque the expression for the linear acceleration of a yo-yo c. Calculate the a of the yo-yo...

An 8kg mass is initally at rest on a 30 degree frictionless incline, it is attached to a hoop shaped 5kg pulley of radius 25.0cm by a massless cord. Find the tension in the cord and the acceleration of the mass using Newton's Laws.

A 5.0kg mass is initally held at rest, attached to a disk shaped 8.0kg pulley of radius 12.0cm by a massless cord. Using Newton's Laws, find the tension in the cord and the acceleration of the mass falling after it is released. Please help

The axle of a 12.0kg solid sphere of radius 0.500m is attached to a suspended 5.00kg weight by a massless cord that passes over a frictionless, massless pulley. When the system is released, the mass drops and the sphere rolls without slipping. Find the tension in the cord and the acceleration of...

Homework Statement an irregularly shaped plastic plate with uniform thickness and density (mass per unit volume) is to be rotated around an axle that is perpendicular to the plate face and through point O. The rotational inertia of the plate about that axle is measured with the following...

Homework Statement Uniform density rod with mass 1.2 kg, length 0.7m rotates around an axis perpendicular to the rod, with angular speed 50 rad/sec. its center moves with a speed of 8m/s. What is the rotational kinetic energy? Homework Equations K= 1/2 I * V^2 (V is angular speed...

A thin slab of material of uniform density with a total mass 3.0 kg is cut in a strange shape: It is bounded by the curves y=4-x^2 and x=0. Initially it is lying in the xy plane. It is free to rotate about the y axi. A force of 8.0 Newtons is constantly applied perpendicular to the slab at the...

Homework Statement I have a question about rotational static equilibrium. When we consider the static equilibrium of a system, I realized that most people only consider the net torque acting on the system. Why don't we need to consider the net force acting on the system? For instance: A...

Homework Statement A hoop rolling on a horizontal surface with a speed v=3.3m/s when it reaches a 15 deg incline.How far up the incline does it go?How long will it be on the incline before it reaches the botttom? Homework Equations I=mr2 conservation energy going up=2gyf=r2+vi2...

Homework Statement A merry-go-round has a mass of 1640 kg and a radius of 7.50 m. How much net work is required to accelerate it from rest to a rotation rate of 1.00 revolutions per 8.00s? Assume it is a solid cylinder. Homework Equations \DeltaKE=Wnet=1/2(Iw2)=14211.7J...

Homework Statement A grinding wheel is a uniform cylinder of with a radius of 8.50 cm and a mass of 0.580 kg. Calculate a) its moment of inertia about its center, and b) the applied torque needed to accelerate it from rest to 1500 rpm in 5.0 s if it is known to slow down from 1500 rpm to rest...

Homework Statement A spool of wire mass m and radius r is unwound under a constant force F. Assuming that the spool is a uniform solid cylinder that does not slip, show that the acceleration of the center of the mass is 4F/3m Homework Equations F+f=ma f=ma-F \tau =I\alpha=Fr-fr...

Homework Statement A giant yo-yo of mass 400 kg measuring about 1.2 m in radius was dropped from a platform 63 m high. One end of the string was tied to the platform, so the yo-yo unwinds as it descended. Assuming that the axle of the yo-yo has a radius of .1 m, find the velocity of descent at...

What force does work on a ball as it is rotating down an inclined plane? Explain why the other forces the ball experiences do not do work. I think the ball experiences gravitational, normal, and frictional forces. Is the force that actually does work on the ball just gravity? I'm having a...

Four children stand at the edge of a circular horizontal platform that is free to rotate about a vertical axis. Each child has a mass of 35 kg and they are at positions that are a quarter-circle from each other. The platform has a moment of inertia equal to 500 kg*m^2 and a radius of 2.0 m. The...

Homework Statement A plyground merry go round of radius r=2m had a moment of inertia of I=250kg/m2 and is rotating at 10rpm about a frictionless verticle axle.Facing the axle a 25kg child hops onto the merry go round and manages to sit down on its edge.What is the new angular speed of the...

Homework Statement A 45kg figure skater is spinning on the toes of her skates at 1.0 rev/s. Her arms are outstretched as far as they will go/ In this orientation, the skater can be modeled as a cylindrical torso (40kg, 20cm average diameter, 160cm tall) plus two rod-like arms (2.5kg each, 66cm...

A barbell consists of two small balls, each with mass 400 grams (0.4 kg), at the ends of a very low mass rod of length d = 35 cm (0.35 m). The center of the barbell is mounted on the end of a low mass rigid rod of length b = 0.525 m (see Figure). The apparatus is started in such a way that...

Homework Statement A uniform solid cylinder and a uniform cylindrical shell are placed side by side at the top of an incline.If they sre released from rest and roll without slipping, A)Determine their speeds when they reach the bottom B)Which objet reaches the bottom first? Homework...