Rotational Definition and 1000 Threads

Hi all, this is not actually homework or similar but the board seemed as the appropriate place for the question. I have an arm of 1m length pointing upwards from a rotation axis, on the end of the arm is a mass of 1kg, upon release the arm starts rotating downwards due to gravity (no other...

This is a spoiler for all Artificial gravity space crafts. If somebody thinks that he can do whatever he can on earth, on the Space Craft, then here is bad news: No football, no soccer, no cricket, no birds can exist on the craft without confusion. :confused: Here is why: A projectile...

Homework Statement A solid steel sphere of radius 10 cm and a mass of 1.5 kg rolls down a 1.25 m incline that makes an angle of 20 degrees with the horizontal. Calculate the linear velocity of the following points relative to the ground, when it reaches the bottom of the incline. a) The...

1. A uniform rigid rod of length L and mass M is attached to a frictionless pivot point at one end. The rod is initially held completely horizontal and is released from rest. What is the linear and angular velocities at the instant the rod is in the vertical position?2. -ΔU = ΔK 3. -ΔU =...

Homework Statement A rotating bicycle wheel has an angular speed of 2.84 rad/s at some instant of time. It is then given an angular acceleration of 1.75 rad/s2. A chalk line drawn on the wheel is horizontal at t = 0. What angle does this line make with its original direction at t = 1.77 s...

Homework Statement A block slides down a frictionless half-pipe (shown on the back of this page). It is released from rest at the point (2,0). Determine the velocity, tangential accleration, radial acceleration and angular acceleration when the block goes through angular displacements of 30...

Homework Statement This is not a homework question, I was just curious. I'm trying to find the angle θ that an unbalanced arm produces in the following case: Homework Equations τ=rF The Attempt at a Solution τ1=τ2 rF=rF r(98 N)(cos θ)=r(49 N)(cos θ) However, the cos θ...

Its not actually a homework . i am just wondering . If we have 2 masses M and m where m rotates about M on either orbit1 of radius R with speed V or orbit 2 of radius r with seepd v , wouldn't its speed ratio V/v equal the following V/v = (sqrt(GM/R))/(sqrt(GM/r)) where G is gravitation...

Homework Statement I have a wheel with a diameter of 1.4m and the radius of gyration is 0.42m. The wheel has a mass of 13kg. Calculate maximum rotational kinetic energy. Homework Equations The Attempt at a Solution From this all i can do is calculate the moment of inertia which...

Homework Statement Consider a small box of mass m sitting on a wedge with an angle θ and fixed to a spring with a spring constant k and a length in a non-stretched state L. The wedge rotates with an angular velocity ω around the vertical axis. Find the equilibrium position of the box...

Homework Statement 4. (9) On an old style record turntable a small rubber wheel is used to drive the larger platter. They are mounted so that their circular edges touch and do not slip while in motion. The small wheel has a radius of 2.0 cm and accelerates at the rate of 3.5 rad/s2 while it...

1. I'm doing an experiment where I have a brass hollow cylinder, and I roll it down an inclined plane, and after each trial, I add fish weights to the inside of it to increase the mass. I'm testing the proportionality between mass and angular velocity, with my hypothesis being an inverse...

An green hoop with mass mh = 2.4 kg and radius Rh = 0.18 m hangs from a string that goes over a blue solid disk pulley with mass md = 2.4 kg and radius Rd = 0.09 m. The other end of the string is attached to a massless axel through the center of an orange sphere on a flat horizontal surface that...

Hi, I'd like to know the solutions for these equations, and how to arrive at them. Is it possible to derive the general form of F(x,y,z) analytically? I'm still studying linear differential equations so I have no clue on what to do with partial differential equations... div F = 0 curl F = 0...

we have in rotational motion a=rω,where r and ω are the radius of rotation and angular velocity respectively.What is a (tangential acceleration or centripetal acceleration)

A thin spherical shell lying on a rough horizontal floor is hit by a cue in such a way that the line of action of force passes through the centre.so there is no torque and it moves with a linear velocity V and no angular velocity.the linear velo is to be founded when the shell starts purely...

Homework Statement Mountaineers often use a rope to lower themselves down the face of a cliff (this is called rappelling). They do this with their body nearly horizontal and their feet pushing against the cliff. Suppose that an 82.0 kg climber who is 1.90m tall and has a center of gravity...

Homework Statement Flywheels are large massive wheels (disks) used to store energy. They can be spun up slowly, and then the wheel’s energy can be released quickly to accomplish a task that demands high power. A large flywheel has a 2.4 m diameter and a mass of 300 kg. Its maximum angular...

Homework Statement A juggler is able to handle four balls simultaneously. He takes 0.5 s to cycle each ball through his hands, throw the ball, and be ready to catch the next ball. (a) With what velocity must he throw each ball up? (b) What is the position of the other three balls when he...

Homework Statement A uniform thin rod of weight W = 100 N is supported horizontally by two vertical props at its ends. At time t = 0 one of the these supports is kicked out. Find the force on the other support immediately thereafter. Homework Equations F1 + F2 = mg The Attempt...

A solid sphere of mass m is released from rest from the rim of a hemispherical cup so that it rolls along the surface. If the rim of the hemisphere is kept horizontal, find the normal force exerted by the cup on the ball when the ball reaches the bottom of the cup.

Homework Statement A dumbbell is made of a rod length L and mass M, and 2 spheres of radius r and mass m (see figure). The rod is attached at a distance L/3 from the left end to a rotational axis A. The dumbbell is let go under gravity and makes a rotational motion under gravity around the...

A horizontal vinyl record of mass 0.10 kg and radius 0.1 m rotates freely about a vertical axis through its center with an angular speed of 4.7 rad/s. The rotational inertia of the record about its axis of rotation is 0.0005 kg*m^2. A wad of wet putty of mass 0.020 kg drops vertically onto the...

Hi everybody, This is my first post in this forum although I started following it some time ago. My question is related to rotational properties involving harmonic oscillator model. Homework Statement We are told to evaluate the expectation value of the rotational constant of a...

Homework Statement The picture shows an overhead view of a ring that can rotate about its center like a merry-go-round. Its outer radius R2 is 0.7 m, its inner radius R1 is R2/2, its mass M is 7.3 kg, and the mass of the crossbars at its center is negligible. It initially rotates at an angular...

Two points are on a disk that rotates about an axis perpendicular to the plane of the disk at its center. Point B is 2.00 times as far from the axis as point A. If the linear speed of point is V, then the linear speed of point A is I know the speed of A must be less and i think its V/4. Is...

Two identical merry-go-rounds are rotating at the same speed. One is crowded with riding children; the other is nearly empty. If both merry-go-rounds cut off their motors at the same time and coast to a stop, slowed only by friction (which you can assume is the same for both merry-go-rounds)...

If we have a ball rolling down from inclined roof that has bottom part at certain height about the ground. I want to know where does the ball land after it leaves the roof. So at this point potential energy is transferred to kinetic (rotational + translational). My question is: What is the...

This isn't really a homework problem, more of a "I'm-building-something-and-need-to-make-sure-the-physics-are-right-before-I-build-something-impractical" problem. Homework Statement Homework Equations The Attempt at a Solution (I grouped it all together, easier for me to not separate each...

Rotational Inertia "Four point masses problem--diagonal" Homework Statement Four point masses of 3.0 kg each are arranged in a square on mass-less rod. The length of a side of the square is .50 m. What is the rotational Inertia for rotation about an axis passing through masses A and C...

Homework Statement A turntable must spin at 33.3RPM (3.49 rev/s) to play an old fashioned vinyl record. How much torque must the motor deliver if the turntable is to reach its final angular speed in 2 revolutions, starting from rest? The turntable is a uniform disk of diameter .305m and mass...

Homework Statement A bowling ball made for a child has half the radius of an adult bowling ball. They are made of the same material (and therefore have the same mass per unit volume). By what factor is a) mass and b) rotational inertia if the child's ball reduced compared with the adult ball...

Homework Statement There is a dumbbell with two masses attached at each end, rotating about a point. The distance between the two masses is R, and the two masses do not have the same mass. m1 < m2 If the angular velocity ω is held constant, by what factor must R change to double the...

Homework Statement Give two reasons why as molecular size increases does it become increasingly difficult to experimentally obtain well-resolved rotational spectra? The Attempt at a Solution Basically I know one reason. The energy levels become more tightly packed. I have another...

I need help with this physics problem! Please help I'm completely stuck. A beam 3m long is free to pivot up and down about the end attached to a wall. The mass of the beam is 25 kg and the cable supporting the beam can support a maximum force of 1800 N. What is the maximum mass that a man...

Homework Statement A puck, mass m, on the end of a (thin, light) string rotates in a circle of radius r_0 at a speed v_0 on a frictionless table. The radius of the circle is slowly reduced from its initial value by pulling the string through a hole in the table. A. Hence write down an...

Homework Statement An electric turntable 0.710 m in diameter is rotating about a fixed axis with an initial angular velocity of 0.230 rev/s. The angular acceleration is 0.887 rev/s^2. A. Compute the angular velocity after a time of 0.192 s. B. Through how many revolutions has the blade...

Homework Statement A solid ball is released from rest and slides down a hillside that slopes downward at an angle 69.0 degrees from the horizontal. What minimum value must the coefficient of static friction between the hill and ball surfaces have for no slipping to occur? Homework Equations...

problem 1: Homework Statement this isn't quite a problem but a general confusion about how to setup the problem. for example: a cylinder of radius R with mass M has a force T applied at its center of mass, pointing horizontally to the right. assuming the cylinder only rolls without...

rotational motion, energy conservation problem URGENT please help Homework Statement A uniform rod of mass M=2 kg and length L = 2m is pivoted from its end. It has a point mass m=1 kg on its tip. It stars from rest at an angle of 30 degrees above horizontal. It falls under the influence of...

centripetal and tangential acceleration in rotational motion...? consider a stone attached to a string moving in a horizontal circle in a gravity field. now it has two accelerations one along the \hat{r} direction and the other along \theta\hat{} (theta hat) direction but there is only one...

Homework Statement A quarterback throws a pass that is a perfect spiral. In other words, the football does not wobble, but spins smoothly about an axis passing through each end of the ball. Suppose the ball spins at 9.0 rev/s. In addition, the ball is thrown with a linear speed of 21 m/s at an...

I have the working for part d) but I don't understand certain parts, so my problems lie with part d), f) and g) Homework Statement 3. A solid wooden disk is suspended as shown: it has mass 7.70 kg and radius 0.219 m . It is rotated from rest about its vertical axis, reaching an angular...

Homework Statement My question relates to a physics problem dealing with the orbit of a moon. In the problem, the orbit of the moon shrinks such that its radius to the center of the planet in question (here, Earth) is smaller. The question gives a great deal of information, but at one point...

Homework Statement Consider a bead of mass m that is confined to move on a circular hoop of radius r. The axis of symmetry of the hoop is horizontal, and the hoop is rotating about a vertical axis at a uniform rate \omega. Neglect friction and assume a constant gravitational acceleration of...

Homework Statement A gymnast with mass m1 = 48 kg is on a balance beam that sits on (but is not attached to) two supports. The beam has a mass m2 = 121 kg and length L = 5 m. Each support is 1/3 of the way from each end. Initially the gymnast stands at the left end of the beam. 1)What is the...

Homework Statement A spherical bowling ball with mass m = 3.4 kg and radius R = 0.115 m is thrown down the lane with an initial speed of v = 8.5 m/s. The coefficient of kinetic friction between the sliding ball and the ground is μ = 0.27. Once the ball begins to roll without slipping it moves...

Rotational Speed of Car tyre? hey guys i was trying to figure out this rotational speed of car tyre?...i have with me the diameter of the car tyre and the distance which it is traveling and the length of the car...so can anyone help? i need to find out how much times will the tyre spin and at...

a) Two objects attract each other with a gravitational force of magnitude 9.30 x10-9 N when separated by 19.4 cm. If the total mass of the objects is 5.06 kg, what is the mass of each? Heavier mass_______kg Lighter mass______ kg my attempt: F=Gm1m2/r^2 so I rearranged to get m1 and m2...

Hi guys so this is my first time posting a question on this amazing forum, i hope i am doing this right since i read that no one will help me if i am missing something. Anyways, i am dealing with a physics problem that it driving me crazy (mainly because my teacher does not explain anything!)...