In physics, angular frequency ω (also referred to by the terms angular speed, radial frequency, circular frequency, orbital frequency, radian frequency, and pulsatance) is a scalar measure of rotation rate. It refers to the angular displacement per unit time (for example, in rotation) or the rate of change of the phase of a sinusoidal waveform (for example, in oscillations and waves), or as the rate of change of the argument of the sine function.
Angular frequency (or angular speed) is the magnitude of the vector quantity angular velocity.One revolution is equal to 2π radians, hence
ω is the angular frequency or angular speed (measured in radians per second),
T is the period (measured in seconds),
f is the ordinary frequency (measured in hertz) (sometimes symbolised with ν).
Homework Statement
Two people start at the same place and walk around a circular lake in opposite directions. One has an angular speed of 1.7*10-3 rad/s, while the other has an angular speed of 3.4*10-3 rad/s. How long will it be before they meet?
Homework Equations
w=\theta/Delta t...
A 3.0-m-diameter merry-go-round with rotational inertia 120 kg*m2 is spinning freely at 0.60 rev/s. Four 25-kg children sit suddenly on the edge of the merry-go-round. (a) Find the new angular speed in rev/s. (b) Determine the total energy lost to friction between the children and the...
Homework Statement
A truck has acceleration A. Its door has a width w and a heigth h. We want to find the angular speed of the door when it reaches the horizontal. (I attached the problem as an image)
Homework Equations
See solution attempt.
The Attempt at a Solution
There is a fictitious force...
Homework Statement
A playground merry-go round of Radius R=2.00m has a moment of
inertia I = 250 kg.m^2 and is rotating at 10.0 rev/min about a frictionless
vertical axle. Facing the axle a 25.0kg child hops onto the merry go round
and manages to sit down on the edge. What is the new...
Homework Statement
Express each of the following in radians per second: (a) 720 ; (b) 50 ; (c) 1000 ; (d) 1 (which is the angular speed of Earth in its orbit).
Homework Equations
why all my answers are wrong?
please help me!
The Attempt at a Solution
Gyroscope-- Angular Speed, Rotational Kinematics, Precession
Homework Statement
A Gyro Stabilizer. The stabilizing gyroscope of a ship is a solid disk with a mass of 6.50×10^4 kg; its radius is 2.30m, and it rotates about a vertical axis with an angular speed of 500 rev/min.
1) How much...
A small 13.0-g bug stands at one end of a thin uniform bar that is initially at rest on a smooth horizontal table. The other end of the bar pivots about a nail driven into the table and can rotate freely, without friction. The bar has mass 70.0 g and is 90 cm in length. The bug jumps off in the...
In an old-fashioned amusement park ride, passengers stand inside a 4.9-m-diameter hollow steel cylinder with their backs against the wall. The cylinder begins to rotate about a vertical axis. Then the floor on which the passengers are standing suddenly drops away! If all goes well, the...
Homework Statement
What is the angular speed of the tip of the minute hand on a clock, in rad/s?
Homework Equations
I thought the equations needed would be angular velocity= change of theta/change in time.
The Attempt at a Solution
I worked on this one and am sure it has a...
Hi all, my homework question is this:
1. What is the angular speed in rad/s of a point on the equator of venus? (Rotation period: 243 days)
2. What is the angular speed in rad/s of a point on the surface of venus at latitude 11 degress south?
I know this isn't that difficult but I can't...
Homework Statement
You point a laser flashlight at the moon producing a spot of light on its surface. At what minimum angular speed must you sweep the laser beam in order for the light spot to streak across the moon's surface with speed v>c? Why can't you transmit information between...
Hi~
This is the question i got
A yo-yo has radius 8.00cm and mass 0.180kg with small hoop.
The yo-yo is released at rest and after yo-yo
descended 75.0cm calculater the angular speed of the rotating yo-yo
and the speed of its center.
I tried to use K=1/2Mv^2+1/2IW^2 but i got weird...
Homework Statement
A uniform stick 1.0 m long with a total mass of 220 g is pivoted at its center. A 3.2 g bullet is shot through the stick midway between the pivot and one end The bullet approaches at 250 m/s and leaves at 140 m/s
With what angular speed is the stick spinning after the...
1. A wheel 2.00m in diameter lies in a vertical plane and rotates with a constant angular acceleration of 4.00 rad/s^2. The wheel starts at rest at t=0, and the radius vector of a certain point P on the rim makes an angle of 57.3 with the horizontal at this time. At t=2, find the angular speed...
[SOLVED] Angular speed problem
Homework Statement
A cylinder with mass m1 = 4.00kg, and radius 30cm, rotates about a vertical, frictionless axle with angular velocity of 8.00 rev/s. A second cylinder, this one have a mass of m2 = 3.00kg, and radius 20cm, initially not rotating, drops onto...
let's say a wheel rotates with a constant angular acceleration. Would its angular speed be affected if the radius was changed? It seems that angular speed would be independent of the radius since the angle is just a proportional quantity.
Homework Statement
A string is wrapped several times around the rim of a small hoop with radius 8.00 cm and mass 0.180 kg . The free end of the string is held in place and the hoop is released from rest (the figure ). After the hoop has descended 60.0 cm, calculate angular speed and...
A thin, uniform, rectangular sign hangs vertically above the door of a shop. The sign is hinged to a stationary horizontal rod along its top edge. The mass of the sign is 2.40 kg and its vertical dimension is 45.0 cm. The sign is swinging without friction, becoming a tempting target for children...
[SOLVED] Angular Speed
\tau = r * F
Homework Statement youve got our bicycle upside-down for repairs with its 66 cm diameter wheel spinning freely at 230 rpm. the mass of the wheel is 1.9 kg and is concentrated mostly at the rim. you hold a
wrench against the tire for 3.1s with a normal...
Homework Statement
As a result of friction, the angular speed of a wheel changes with time according to
d θ/d t = ω_0 e^(−σ t) ,
where ω0 and σ are constants.
initial angular speed = 5.45 rad/s
σ =.23913
Determine the number of revolutions the wheel makes after 2.33 s .
Answer in units of...
Homework Statement
An LP turntable must spin at 3.53 rad/s to play a record. How much torque must the motor deliver if the turntable is to reach its final angular speed in 1.9 revolutions, starting from rest? The turntable is a uniform disk of diameter 30.7 cm and mass 0.24 kg.
Homework...
Homework Statement
A disk with a radial line painted on it is mounted on an axle perpendicular to it and running through its center. It is initially at rest, with the line at theta 0 = -90°. The disk then undergoes constant angular acceleration. After accelerating for 3.1 s, the reference...
1. The figure below shows the drive train of a bicycle that has wheels 67.3 cm in diameter and pedal cranks 17.5 cm long. The cyclist pedals at a steady angular rate of 76.5 rev/min. The chain engages with a front sprocket 15.2 cm in diameter and a rear sprocket 7.25 cm in diameter.
2. v...
Homework Statement
A thin 1.0-meter-long rod pivoted at one end falls (rotates) from a horizantal position, starting from rest and with no friction. What is the angular speed of the rod when it is vertical?
Homework Equations
I (of the thin rod) = (1/3)ML^2
The Attempt at a...
How can you find angular speed (average), if its a question of rotation about a fixed axis, and all you know really is the rotational inertia of the system? You have no values of the angles (with regards to the reference axis) and no values for time either.
A merry-go-round of radius R=2.0 m has a moment of inertia I=250 kg m2, and is rotating at 10 rpm. A child whose mass is 25 kg jumps onto the edge of the merry-go-round, by jumping directly toward the center at 6.0 m/s. The new angular speed (in rpm) of the merry-go-round is approximately
A)...
[SOLVED] angular speed.
Homework Statement
In 9.8 s a fisherman winds 2.6 m of fishing line onto a reel whose radius is 3.0 cm (assumed to be constant as an approximation). The line is being reeled in at a constant speed. Determine the angular speed of the reel.
rad/s
Homework...
Homework Statement
Under some circumstances, a star can collapse into an extremely dense object made mostly of neutrons and called a neutron star. The density of a neutron star is roughly 10^{14} times as great as that of ordinary solid matter. Suppose we represent the star as a uniform...
Homework Statement
I need to know how to convert angular speed into revolutions
Homework Equations
W=2*pi/60 sec, but that's for rad over second
The Attempt at a Solution
w=2*pif
Homework Statement
A string is wrapped several times around the rim of a small hoop with radius 8.00 cm and mass 0.180kg. The free end of the string is held in place and the hoop is released from rest (the figure View Figure ). After the hoop has descended 95.0cm, calculate
the angular...
[SOLVED] Torque & Angular Speed
Homework Statement
The wheel of an engine has a moment of inertia 2.80kgm^2 about its rotation axis.
What constant torque is required to bring it up to an angular speed of 360 rev/min in a time of 7.60 s, starting from rest?
What is its final...
A 22 kg child jumps onto the rim of a 110 kg rotating disk of radius 2.9 m. If the angular speed of the disk before the child's jump was 2.1 rad/s what is the angular speed of the disk-child system?
I got no idea how to start this problem or what formula to use. please help me solve this...
Homework Statement
A 60kg skater begins a spin with an angular speed of 6 rad/s. By changing the position of her arms, the skater decreases her moment of intertia by 50%. What is the skater's final angular speed?
Homework Equations
I understand that I=m*(r^2), so if the radius decreases...
A flat uniform circular disk (radius = 4.69 m, mass = 280 kg) is initially stationary. The disk is free to rotate in the horizontal plane about a frictionless axis perpendicular to the center of the disk. A 55.0-kg person, standing 1.59 m from the axis, begins to run on the disk in a circular...
A flat uniform circular disk (radius = 4.69 m, mass = 280 kg) is initially stationary. The disk is free to rotate in the horizontal plane about a frictionless axis perpendicular to the center of the disk. A 55.0-kg person, standing 1.59 m from the axis, begins to run on the disk in a circular...
Homework Statement
A nonuniform 2-0 kg rod is 2.0 m long. The rod is mounted to rotate freely about a horizontal axis perpendicular to the rod that passes through one end of the rod. The moment of inertia of the rod about this axis is 4.0 kg.m2. The center of mass of the rod is 1.2 m from the...
Homework Statement
A grindstone of radius 4.0m is initialy spinning with an angular speed of 8.0 rad/s. The angular speed is the increased to 10rad/s over the next 4.0 seconds. Assume that the angular acceleration is constant. What is the average angular speed of the grindstone?
Homework...
I've seen several examples of using Navier Stokes in a rotating container where gravity is purely in the Z direction. These solutions generally used cylindircal coordinate systems.
I wanted to attempt this problem where the gravity vector does not point purely in the Z direction. (ie...
I've attached the problem as an image. I solved 20 and 21 very easily. For 22, my obvious instinct was to set dtheta/dt to 0, but that's an unsolvable equation. I'm obviously missing something key in solving 22. What is it?
Homework Statement
http://loncapa2.physics.sc.edu/res/msu/physicslib/msuphysicslib/21_Rot3_AngMom_Roll/graphics/prob21a_bar.gif
On a frictionless table, a glob of clay of mass 0.38 kg strikes a bar of mass 0.90 kg perpendicularly at a point 0.55 m from the center of the bar and sticks to it...
http://www.hpcsoft.com/products/MathSoL/geom/cylinder.jpg
A cylinder is rotating with angular speed
-- take some points along radius and find if they have same angular speed ?
---- same tangential speed ?
------ same tangential acceleration ?
I think that they will have will same...
An amusement park ride consists of airplane-shaped cars attached to steel rods. Each rod has a length of 14.2 m and a cross-sectional area of 7.80 cm^2. Each car plus two people seated in it has a total weight of 1950 N.
When operating, the ride has a maximum angular speed of 7.50 rev/min...
A top has a moment of inertia of 4.40 10-4 kgm2 and is initially at rest. It is free to rotate about the stationary axis AA'. A string, wrapped around a peg along the axis of the top, is pulled in such a manner as to maintain a constant tension of 5.19 N. If the string does not slip while it is...
A coin with a diameter of 2.20 cm is dropped on edge onto a horizontal surface. The coin starts out with an initial angular speed of 15.9 rad/s and rolls in a straight line without slipping. If the rotation slows with an angular acceleration of magnitude 1.76 rad/s2, how far does the coin roll...
A coin with a diameter of 2.20 cm is dropped on edge onto a horizontal surface. The coin starts out with an initial angular speed of 15.9 rad/s and rolls in a straight line without slipping. If the rotation slows with an angular acceleration of magnitude 1.76 rad/s2, how far does the coin roll...
I having trouble answering this one. I already had to calculate the change in potential energy but am now stuck.
A stick with a mass of 0.168 and a length of 1.00 is pivoted about one end so it can rotate without friction about a horizontal axis. The meter stick is held in a horizontal...
I am interested in the fllowing issue and I would appreciate any help:
I need a motor that has a variable angular speed. To be more exact: the angular speed needs to be a f(1/sin(theta)) where theta is the angle of rotation varying between 1 to 89 degrees.
Does anyone know if this type of...
Angular Speed Question, Please Help!
I have this question I am stuck on and I don't understand and need help:
In a neutron velocity selector, two thin discs of a neutron absorbing material are rigidly mounted on a shaft 1 meter apart and rotated with constant angular speed of 1000...
Could anyone please help me figure out how to approach this problem?
Space stations have been proposed to accommodate the surplus population of the Earth. The initial design is for a hollow, uniform, cylindrical space station of diameter 3.15 km, length 10.35 km, and total mass of 1.19 x...
A merry go round can be described as a horizontal platform in the shape of a disc which rotates on a frictionless bearing about a vertical axis through its centre. The platform has a mass of 150 kg, a radius of 2.0 m and a rotational inertia of 300 kg.m2.A 60 kg student walks slowly from the rim...