Angular velocity Definition and 841 Threads

Homework Statement Show, by conservation of energy, that when a length, L, of string has unwound that a yo-yo is spinnning with angular velocity Remember the yo-yo has both linear and rotational velocity Homework Equations \omega= \sqrt{}gL/R^{2} The Attempt at a Solution I do...

Homework Statement http://img707.imageshack.us/img707/2066/question3.jpg Homework Equations v = r' \hat{r} + r*θ' (^θ) The Attempt at a Solution I was sure I knew how to do this question but made a mistake somewhere, because my answer is not right. So here is my working out. l r' l =...

If so, wouldn't gamma would be like? (1 - w^2 / c^2)^-1/2 or (1 - v^2 / r^2c^2)^-1/2

Homework Statement At the instant shown in the figure , the crane's boom has an angle = 33.0 and rotates around the vertical axis with angular velocity = 8.00×10^−2 radians/s that increases at the rate = 7.00×10^−2 radians/s^2. At the same instant, the crane's boom is rotating upward...

Can anyone explain why angular velocity is perpendicular (or goes up and down) to the circular motion I know that angular velocity measures the change angle over time, so wouldn't that mean the angular velocity is parallel to the circular motion since the angles are measured parallel to the...

Been sick for a bit so missed a fair bit of "advanced" maths including locuses, particularly parabolas, but what's worrying me more at the moment is dynamics. So got a moderately difficult question here to help catch me up. I don't really comprehend any of the rules and this question is tricky...

Homework Statement A 7kg plate with a radius of 1.4m is rotating at 63 rad/s around an axis perpendicular to its center. Another plate that is not rotating is dropped onto the first plate and their centers align. The second plate is 5kg, with a radius of .8m. What is the angular velocity of...

I'm thinking of making an electricity generator which is rotated by hand, or possibly something like wind, or gerbils on a treadmill etc etc.. Anyway, the current and emf produced would vary depending on the velocity at which the generator is turned, correct? I therefore need a way of keeping...

Can anyone explain to me how angular velocity (w) = 2pi(f) -->where f = frequency. This is not a homework question involving numbers. I'm reading a section on "the period of sinusoidal Nature of SHM" and I don't understand how they get this equation.

Homework Statement Compute the angular velocity (ω) when the arm reaches 45 degrees equation = ω^2 = ωi^2 + 2α(Δθ) α = 196.85 Homework Equations equation = ω^2 = ωi^2 + 2α(Δθ) The Attempt at a Solution 2(196.85)(45) ?? what do i use for ωi^2? or is it just 0

Homework Statement In the Bohr Model of the Hydrogen Atom, a single Electron orbits a circle round a single stationary Proton. If the radius of the electron's orbit for its lowest energy state (the "ground state") is 5.3x10^-11m, find the the constant speed, v , of the orbiting electron...

Homework Statement The attempt at a solution I think the answer is (b) because an increase in mass would cause an increase in inertia of Earth. This would decrease the velocity of Earth, and since velocity is proportional to angular velocity, both would decrease. Am I right?

There is a cross shaped object with masses on each arm, the arms are different lengths and they are perpendicular to each other. the longer rod, (7m radius from center) has two 12kg masses, one on each end. The shorter rod (3.5m radius from center) has two 24kg masses one on each end...

Homework Statement Use conservation of energy to determine the angular speed of the spool shown in the figure below after the 3.00 kg bucket has fallen 3.90 m, starting from rest. The light string attached to the bucket is wrapped around the spool and does not slip as it unwinds. relevant...

Homework Statement Suppose a record turntable rotates at constant angular velocity. a) Does a point on the rim have radial and/or tangential acceleration? b) If the turntable's angular velocity increases uniformly, does the point have radial and/or tangential acceleration? c) For which...

Homework Statement I am studying for my physics test on tuesday and i came across this problem and i thought i got it right after i worked through it but it was wrong. A playground merry-go-round is at rest, pivoted about a frictionless axle. A child of mass 40 kg runs along a path...

Homework Statement A uniform sphere of mass m and radius R rotates around the vertical axis with angular speed \omega. Two particles of mass m/2 are brought close to the sphere at diametrically opposite points, at an angle \Theta from the vertical. The masses, which are initially essentially...

Homework Statement A 200 g, 42.0-cm-diameter turntable rotates on frictionless bearings at 56.0 rpm. A 20.0 g block sits at the center of the turntable. A compressed spring shoots the block radically outward along a frictionless groove in the surface of the turntable. What is the...

what is angular velocity? would be pleased if someone helped.

Homework Statement I had a physics lab and we found the 3 trials of revolution in 2 min then the result came as 1st=344rev 2nd=332rev 3rd=330rev (These numbers is from the calculation of Final (2min) - Initial start) Then it asked to find the average angular velocity for three of...

A uniform rod of mass 0.62 kg is 6 m long. The rod is pivoted about a horizontal, fric- tionless pin at the end of a thin extension (of negligible mass) a distance 6 m from the cen- ter of mass of the rod. Initially the rod makes an angle of 48◦ with the horizontal. The rod is released...

where x represents cross product currently if i forget i figure these out using the right hand rule, but how do you get each equation visa versa using vector algebra i started with w = rxv how do you derive that v = wxr i got up to this w = rxv w= -(vxr) rxw = -rx(vxr) rxw =...

Homework Statement Which is equal to zero if angular velocity is constant, normal or tangential acceleration? The one with zero angular velocity is a crank. The crank moves at a fixed point. Homework Equations The Attempt at a Solution

If we have a bar AB which can rotate about A and there is a force applied on AB, make it rotate. Is there any formula for us to calculate the angular velocity of this bar?

Homework Statement a small puck of mass .5kg is executing Uniform constant motion on a friction free horizontal table. The angular frequency of the puck is 10 sec-1 (counter clockwise) and the radius of the circular motion is .8m. the radius stays fixed as the student holds the string in...

In an example question the revolutions per minute where 500rev/min. The question asked how many revolutions the disk makes in 5.5s. The solution started with the formula w=w_o+\alpha t I'm wondering why one can't just convert rev/min into raidans/sec and multiply that number by 5.5s? kind of...

I have a problem, I am a video game programmer. I have a car that bump into objects. At a given time I want it to stop to rotate in any direction. But the angular velocity still continue. Any idea how to conter the angular velocity?

Homework Statement A certain yo-yo can be modeled as a uniform cylindrical disk with mass M and radius R and a lightweight hub of radius ½R. A light string is wrapped around the hub. (a) First, the yo-yo is allowed to fall. Find the angular velocity of the yo-yo when the string has...

I think I've gotten it but figured it would be best to get a second opinion because I feel like I made a few leaps of faith. I sincerely appreciate your time. <3 Homework Statement A 1.0 kilogram object is moving horizontally with a velocity of 10m/s, when it makes a collision with the lower...

angular velocity --velocity conversion I am a bit confused about angular velocity --velocity conversion . I thought of a problem in my mind which is as follows There is a particle moving with velocity v in certain direction as shown in the figure.and I want to calculate the angular...

Homework Statement If V= Sin[wt] where w = angular velocity t is time in radians How do you find RMS Voltage Does RMS voltage depend on angular velocity of sin wave? Homework Equations The Attempt at a Solution i integrated from 0 to PI radians and left with a sin...

hi, i am trying to solve this question. A thin stick of mass M = 4.9 kg and length L = 2.6 m is hinged at the top. A piece of clay, mass m = 1.0 kg and velocity V = 4.9 m/s hits the stick a distance x = 2.20 m from the hinge and sticks to it. What is the angular velocity of the stick...

Homework Statement The block moves to the left with a constant velocity v. a)determine the distance x as a function of Q . b)determine the Angular velocity as a function of Q c)determine the Angular acceleration as a function of Qhttp://img98.imageshack.us/img98/3691/16293179.jpg Homework...

Homework Statement A speaker is attached to a wire 1.5 m long and is spun in a circle at 2 rev/s. The speaker is connected to an electric piano on which a child is playing a note at 261 Hz. Speed of sound in air is 343 m/s. What range of frequencies will the stationary observer hear? I...

Hi people, i had my final exam yesterday, and one of the questions was this "a particle in uniform circular motion, moved for an interval of 0.185 seconds in a circular path of radius 16 cm, what is the angular velocity of the particle"? I think that the question lacks information, am i right?We...

Hello, I am having a problem calculating the angular velocity of a bouncing ball. At first this ball is thrown a distance and then hits the ground. Before it hits the ground it has no angular velocity. After it hits the ground it gets an angular velocity. I have the inertia of the ball...

Homework Statement http://online.physics.uiuc.edu/cgi/courses/shell/common/showme.pl?courses/phys211/oldexams/exam3/fa07/fig19.gif A dumbbell consists of a slender rod of negligible mass and length L = 1 m and small steel balls attached to each end with mass 1 kg and 2 kg, respectively. It...

I had 2 questions: 1. My textbook derives that the equation from lenz's and faraday's law emf = - d(N*flux)/dt = B * dA/dT where dA/dt = length * speed However, why does the N value disappear in the new equation? Also, this question is given after: 2. A metal propeller...

Homework Statement Consider the conical pendulum, a mass on the end of a string, with the other end of the string fixed to the ceiling. Given the proper push, this pendulum can swing in a circle at an angle theta of 25.5 degrees with respect to the vertical, maintaining the same height...

Homework Statement A horizontal bar of mass 3.0 kg and length 1.0 m is free to rotate about a vertical axis through its center. A clay blob of mass 1.0 kg traveling at a velocity of 2.0 m/s in the direction shown collides with the end of the bar and sticks to it. Find the magnitude of the...

Homework Statement I am given the attached graph (excuse my abysmal homemade graph!). On the y-axis, I presume that it is displacement (x). The x-axis is time. This graph looks like SHM, but I could be wrong! The graph rises from 0 to 2 every 2 seconds, and drops back to 0 on the y-axis...

Angular veloity, tangential velocity and acceleration ect.. blahh okay so we've gon over it is class but it still confuses me... some of the forumal's I've remembered are s=(theta)r (theta)=s/r anyways I am not sue how to find the tangential velocity and angular velocity what's the...

Homework Statement Okay, imagine there is a rod floating in space, except its not moving and not rotating. you are stationary next to the rod. you decide to push the rode with your finger at a spot "x" distance away from it's centre of mass. how much of that force will turn into plain speed...

Homework Statement a wheel rotates with a constant angular acceleration pie rad/s^2. during a certain time interval its angular displacement is pie rad. at the end of the interval its angular velocity is 2pie rad/s. what is the angular velocity at the beginning of the interval? Homework...

Homework Statement A rotating object has angular velocity 10radians/s. After one min through what angle has the object rotated in 1) radians 2) degrees Homework Equations Degrees = Radians x 180/Pi The Attempt at a Solution I have tried and only come up with an answer of...

Homework Statement A 2100lb airplane requires a power of 100 HP at the propeller to climb at an angle of 20 degrees to the horizontal at a constant speed. how much altitude could it gain in 10 minutes? Homework Equations that's actually what I need help on...i left my book at school...

A 4.8m diameter merry-go-round is rotating freely with an angular velocity of 0.8rad/s. Its total moment of inertia is 1950(kg)(m2). Skid, Mitch, Larry, and Greezy all jump on at the same time. They each have a mass of 65kg.What is the angular velocity now? Relevant equations...

Homework Statement 1 m long rotatable bar with a mass of 2 kg is held on vertical stick that goes through its center of gravity. A bullet with mass 0.2 kg is shot with a speed 1 m/s horizontally at the edge of the bar. After the collision the bullet lodges into the bar. Calculate the angular...

A machine rotates at an angular velocity of 1.6rad/s. Its velocity is then increased to 6.2rad/s at an angular acceleration of 0.7rad/s2. (a) How many revolutions does it make during its acceleration? (b) How long does the acceleration take? Sorry I'm not quite sure as how to approach this...

Homework Statement A CD player spins a disc in a clockwise direction when looking at the player from the top. What is the direction of the angular velocity. Homework Equations The Attempt at a Solution OK, the key for this practice exam says the answer is in the -y direction. I...