# Tagged Questions

The time derivative of angular position used when studying rotating objects or systems.

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### fortune wheel - angular acceleration, given initial velocity, radius, angle

I have another physics problem and I'm trying to solve this using formulas I found on the web. I'm an online student and there is no textbook given for our course nor is the topic explained in the ...
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### Correct formulas for two wheeled robot motion

I'm trying to write a simulation of a two wheeled robot, which can be controlled by varying the speeds of his wheels, independently. However, the physics engine that I'm using can only rotate a body ...
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### Change in acceleration due to gravity because of rotation of earth [duplicate]

The formula above is the equation for acceleration due to gravity when earth rotates. G is the original acceleration. Can someone explain how this formula came?
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### Is angular velocity parallel to axis of rotation?

I'm reading the Wikipedia page on angular velocity. It says here of the angular velocity vector in three dimensions that “[t]he magnitude is the angular speed, and the direction describes the axis of ...
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### How can I calculate the torque of draw force which affect on spinning ball flying in the air?

I am studying the Magnus effect on a flying ball i have calculate the magnus force but i trying calculate the angular acceleration, because the angular velocity of the ball is not constant. I have ...
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### Calculating acceleration offset by C.G [duplicate]

I'm trying to calculate the acceleration an accelerometer would read NOT placed in the Center of Gravity of the object. Let's look at the figure below (or in link provided). The accelerometer was ...
According to general relativity the time dilation is given by following formular: $d \tau = \sqrt{g_{\mu \nu} \dot{x^{\mu}} \dot{x^{\nu}}}$ If I'm interestet in the time dilation at the ISCO I set $... 1answer 31 views ### Why does a ball rotate sometimes when you throw it? My guess is that when you throw a ball, which is held by your hand, using you arm, the radius of the circular path being constant, the outermost part of the ball has a bigger radius than the innermost ... 2answers 125 views ### angular velocity of rigid body I am doing some physics for a game. I have a rigid body defined as multiple balls of the same mass distributed to make some object. Let's say I put to each ball a different velocity but because it is ... 0answers 31 views ### Total angular velocity (Kerr metric) I have a problem with the kerr metric and the "rotating spacetime" in the ergosphere. How can i calculate the angular velocity$\omega$of an object in the ergosphere (which flys from infinity into ... 3answers 74 views ### Angular velocity from orientational displacement A 3-dimensional object is rotating around an unknown 3-dimensional axis through the object's center of mass. Its orientation is described by two unit vectors. I know an initial orientation and a final ... 1answer 18 views ### Which part of an angular velocity vector is its direction? I am assuming that an angular velocity vector only has two direction: positive for counterclockwise and negative for clockwise. Just to make sure that I have the right interpretation. Newton's 1st ... 1answer 43 views ### Direction of angular velocity please help me here! Im confused, is direction of angular velocity perpendicular to the plane of motion, or along the plane of motion?? From hyperphysics - http://hyperphysics.phy-astr.gsu.edu/... 1answer 203 views ### How do you calculate theoretical ratios of angular velocity final and angular velocity initial? [closed] I'm asked to calculate the "Theoretical Ratio". ($\omega_f/\omega_i$) I have Inertia of the Disk =$I_{DISK} = .0094115713$, I have Hoop Inner Radius =$I_R = 55.725$So I am supposed to use the ... 0answers 33 views ### How rotational force calculation depends on the distance between the point of force application and the axis of rotation? I don't understand how the perpendicular distance between the point of force and the axis of rotation gets involved in the calculation of the rotational effect of that force.Is it about rotational ... 2answers 275 views ### Need help understanding angular acceleration due to gravity The question asks what the angular acceleration of an uniform disc of radius$R$rotating about an axis passing through its edge if it is released from rest with its center of mass at the same height ... 0answers 36 views ### Unit ball rolling in a straight line on a flat plane, angular velocity as measured in a frame attached to the center of the ball Suppose I have a unit ball rolling in a straight line at a constant velocity on a plane. There is a 3-axis inertial measurement unit (IMU) embedded in the ball at the center (so the ball has an ... 1answer 59 views ### How would the angular velocity of the rod change if it slipped on the table? I wanted to consider a second case of my homework assignment. We were asked to solve the question: A uniform rod of length b stands vertically upright on a horizontal plane in a position of unstable ... 0answers 20 views ### integrating small angular velocities I know that for a constant angular velocity the following is true:$R=e^{W t} R_0$where$W$is an angular velocity tensor,$t$is a time, and$R$is a rotation matrix I believe the following is ... 2answers 97 views ### Spinning an object in vertical circle The situation : A block of mass$M$is tied to a string and is spun around in a vertical circle. The question asks me to calculate the tension in the string 'at the lowest point' after giving ... 2answers 64 views ### Shouldn't the net acceleration in circular motion always be zero? I just learned the derivation of the acceleration vector in circular motion. I know that acceleration vector has two components which are centripetal acceleration($\omega^2ra_r$) and tangential ... 1answer 62 views ### Why the point right below the center of a rolling ball on the ball has zero instantaneous velocity [duplicate] Suppose there is a snooker ball rolling on a table. The velocity of the center of the ball is Rω and its direction is horizontally right. I don't understand why the point right below the center on the ... 1answer 249 views ### A question on deriving a formula for a rotational object I have this question assigned, but I really am stuck on how to do it: A bullet is shot through two cardboard disks attached a distance$D$apart to a shaft turning with a rotational period$T$, as ... 1answer 508 views ### Is Wikipedia's definition of angular velocity incorrect? According to Wikipedia, the general formula for the angular velocity of a particle in three dimensions is $$\boldsymbol \omega = \frac{\mathbf r \times \mathbf v}{\left |\mathbf r\right|^2}.$$ But if ... 1answer 77 views ### How can we find velocity, acceleration etc, of a revolving particle with respect to an observer inside the circle(not at center) A particle is revolving in horizontal a circle of radius$R$with constant speed of$|\vec{v}|$and constant angular velocity$\omega$. There is another observer standing inside the circle, at a ... 2answers 97 views ### Why isn't angular velocity the moment of velocity if angular momentum is moment of momentum? [closed] Angular momentum can be defined as$L$=$\textbf{r}$x$m\textbf{v}$. Why is angular velocity$\omega$then not$\textbf{r}$x$\textbf{v}$, but instead$v = \omega \times \textbf{r}$? 2answers 241 views ### Is$v$not always equal to$\omega r$in angular motion? NB:I am not asking an answer for the question quoted. I had this question given in my book: A ring of radius$R$rolls on a horizontal ground with linear speed$v$and angular speed$\omega =2v/R$... 2answers 92 views ### Can a GPS system detect the decline in the rotational velocity of the Earth? From Wikipedia: Rotation in Angular Velocity of Earth Earth's rotation is slowing slightly with time; thus, a day was shorter in the past. This is due to the tidal effects the Moon has on Earth's ... 1answer 175 views ### How to calculate the “angular braking distance” when you know the following values? I have to calculate the arc length in radians that a circle spinning at speed will travel when it decelerates to$0$. I have the initial angular velocity in rad/s, the radius in meters, the mass in ... 1answer 555 views ### Angular velocity relative to different frames In Goldstein it is said "It is intuitively obvious that the rotation angle of a rigid body displacement, as also the instantaneous angular velocity vector, is independent of the choice of origin of ... 1answer 182 views ### Kinematics of Euler angles relative to a rotating frame I have a rotating body$B$and a rotating frame$F$whose orientations are described by the quaternions$q_B$and$q_F$respectively. I also have the angular velocity vectors$\omega_B$and$\omega_F$.... 1answer 346 views ### How much does air resistance affect the angular velocity of a golf ball? I'm modeling the flight trajectory of a golf ball, and using angular velocity to calculate the Magnus force. Currently, I'm assuming angular velocity to be fixed throughout the ball's flight. How ... 5answers 231 views ### Why does solving$\mu mg = m \frac{v^2}{r}$give the *max* possible velocity? So here is the standard problem setup of a car turning on an unbanked road: A 1000 kg car is going around a curve with radius 30 meters. If the coefficient of friction between the car's tires ... 2answers 185 views ### Intuitive explanation for why centripetal acceleration is$\frac{v^2}{r}$There are several ways to write centripetal acceleration $$\frac{v^2}{r} = \omega^2 r = v \omega$$ Are there intuitive explanations for any of these three forms? For instance, I can sort of explain ... 1answer 80 views ### Moving objects along a radius I'm working on a project involving a Roomba which I'd like to move precisely from coordinate to coordinate. To move the Roomba manually you need to give it a velocity between -500 to 500mm/s and a ... 2answers 277 views ### How to find Tangential/Radial/Angular Velocity for motion in any curve? Is the radial velocity responsible only for changing distance between objects and the component perpendicular to it only for change in direction? If so why? Please try to give a different explanation ... 0answers 27 views ### Can't we assign any other direction for instantaneous angular velocity except along the axis of rotation? [duplicate] We specify the direction of instantaneous angular velocity using the right hand thumb rule. I just want to know that is it just a matter of convention or we don't have any other direction for it to be ... 2answers 687 views ### In which direction does mud fly off a moving bike's tire & why? If a bike moves through a muddy area, mud gets on its tires. Then the mud flies off from the tires. Which forces are acting on it? In which direction does it fly off? On my physics test, I wrote ... 1answer 95 views ### Why do you seem to go faster as you hug a turn? I was driving to work this morning when this question occurred to me. I was going up a clover-leaf entrance ramp to the highway. The person in front of me was lazily floating the outside of the curve, ... 1answer 91 views ### If$\omega = \frac{v}{r}$, why do we need torque? If$\omega = \frac{v}{r}$, then why do we need torque and angular acceleration? The velocity v can be found just by Newton's second law of motion$F = ma => a = F/m$and$v = v_0 + at$. Then we ... 1answer 68 views ### Force responsible for increasing a spiraling object's tangential velocity Suppose we have a small mass attached to a string that has been fed through a hole in the friction-less table on which the mass is rotating. Pulling the string downwards thus decreases the radius of ... 1answer 175 views ### Movement and Rotation of a Inverted-Pendulum-like Object with External Forces I'm struggling to model the movement of a complex object based on an external force. Let's start with a simple example of what I'm looking for. We have a block$b$of mass$M_b$, moving friction-... 1answer 192 views ### Calculating the charge of weights on a rod based on it's movement in an electric field I've got a problem from my physics course which I am a little stuck on. A dumbell consisting of two identical masses m=5.8 kg attached to the ends of a thin (massless) rod of length a=0.4 m that ... 1answer 60 views ### Angular velocity in central force field For motion in a central force field consider a rotating reference frame, which is characterized by the Euler angles$\alpha$,$\beta$,$\gamma$associated with the rotation of the frame of Cartesian ... 2answers 189 views ### How many hours will be in a day if the radius of Earth increases by 70 m? [closed] I am little confused about the linear momentum and angular momentum, will the linear momentum of earth change due to changing of its radius or it will stay as it was and i know that the moment of ... 1answer 167 views ### What causes angular and linear deceleration in a sliding and rotating ring? I was solving an AP Physics problem involving a ring sliding and rotating over a frictional surface. When I started to think about why the ring eventually comes to a stop I started to become confused. ... 3answers 140 views ### Why is acceleration significant to generating power in racket sports? I'm reading a paper on badminton stroke power (see Figure 4 on page 8). It says: For most of the trials the racket head reached peak speed just at the time of impact. The racket head showed ... 3answers 888 views ### How can I relate linear and angular motion using a single formula? I want to relate linear and angular motion using a single formula. Assume I have a 10m rod, and I apply a force of 5N on it, 2.5m away from the axis of rotation for 1s. How can I determine the ... 1answer 283 views ### Equivalency of conditions involving angular momentum of a rolling ball hitting a wall (59th Polish Olympiad in Physics) A ball of mass$m$, radius$r$and a moment of inertia$I = \frac 25 mr^2$is rolling on the floor without sliding with the linear velocity$v_0\$. It hit the wall ...
I know that when the motion of a particle is circular about the origin then: $$\vec v=\vec \omega \times \vec r$$ But that this does not hold for any motion with a radial as well as tangential ...