Angular acceleration Definition and 566 Threads

Homework Statement 13.53 The tension in the sting of the simple pendulum is 7.5N when θ=30deg. Calculate the angular velocity and angular acceleration of the string at this instant. Homework EquationsThe Attempt at a Solution Is this correct?

Homework Statement When the hand is rotating about the wrist in the sagittal plane its centre of mass has an acceleration of 3m/s(squared) in a horizontal direction, its mass is 2kg and the vertical direction (i.e. Y) is against gravity. The hand travels through 30 degrees. If the distance from...

So the equation for angular acceleration on the AP physics sheet reads α = ΣT / I. I am required to prove that the units on each side are the same however I can't figure out how to get the rad/s^2 unit for angular acceleration into the same form as the right side which is N*m/ kgm^2 Any help...

Homework Statement A flywheel turns through 40 rev as it slows from an angular speed of 1.5 rad/s to a stop. (a) Assuming a constant angular acceleration, find the time for it to come to rest. (b) What is its angular acceleration? (c) How much time is required for it to complete the first 20 of...

Homework Statement A pulley hangs of mass, m, and radius, R, hangs from the ceiling. Two blocks of masses, m1 and m2 are connected by a massless, non-stretchable rope on the pulley (assume no slipping). What is the angular acceleration of the pulley and what is the ratio of the tension forces...

Homework Statement Homework EquationsThe Attempt at a Solution [/B] Initially the rod is in rotational equilibrium , so net torque about CM is zero . From torque equation about CM , we get Tension T in the left string = Force F (kx) in the spring Doing a force balance gives us T+F=Mg...

Homework Statement Note : In the above setup the string lengths are unequal and the left angle is 30° and right angle is 60° .Homework EquationsThe Attempt at a Solution [/B] Just after the string is cut , writing force eq. for rod in vertical direction . ##Mg - Tcos60° = Ma_y ## (1)...

Homework Statement A thin uniform rod (of mass 10.0 Kg and length of 1.20 m) is attached to a friction-free pivot. Initially, the rod is balanced vertically above the pivot (position A in the figure attached). If the rod falls from rest, calculate a. the angular acceleration at position B...

Homework Statement The 25-lb slender rod has a length of 6 ft. Using a collar of negligible mass, its end A is confined to move along the smooth circular bar of radius 32√ ft. End B rests on the floor, for which the coefficient of kinetic friction is μB = 0.24. The bar is released from rest...

Homework Statement [/B] A uniform rigid rod with mass Mr = 2.7 kg, length L = 3.1 m rotates in the vertical xy plane about a frictionless pivot through its center. Two point-like particles m1 and m2, with masses m1 = 6.7 kg and m2 = 1.6 kg, are attached at the ends of the rod. What is the...

Homework Statement A constant torque is applied to a pinion which has a moment of inertia of I_m. The pinion(A) drives two gears, one (B) which is connected to a mass which has a moment of inertia = I_m and the other(C) is connected to a mass which has a moment of inertia = 2I_m. The gear...

Consider an ideal fidget spinner, composed of a central disk (a bearing, usually) plus some N disks, all of them of radius L distributed regularly with their centres along a circle of radius R. In the simplest case all of them have the same mass, M, and are able to turn freely without...

Homework Statement The directed beam from a small but powerful searchlight placed on the ground tracks a small plane flying horizontally at a fixed height h above the ground with a uniform velocity v. If the search light starts rotating with an instantaneous angular velocity ##\omega_0## at...

Homework Statement Sir Lost-a-Lot dons his armor and sets out from the castle on his trusty steed in his quest to improve communication between damsels and dragons (Fig. P12.20). Unfortunately his squire lowered the draw bridge too far and finally stopped it 20.0° below the horizontal...

Homework Statement I think I made a mistake somewhere.. Homework Equations T = Jα T = F*R The Attempt at a Solution A) I started with T = Jα Since there is no slip, αm = αL Thus: Tm / Jm = TL / JL Plugging in, we find TL = Tm * JL / Jm = 2560 Now use T = F*R. Tm = Fm * Rm Plugging in...

Homework Statement what is the angular acceleration of the arm when theta equals 45 degrees. v=2 m/s picture is attached Homework Equations law of sites law of cosinesThe Attempt at a Solution [/B] so I used the law of sines to resolve side r as being 579.555 mm now I now I need to take time...

Homework Statement "A drum of 60-mm radius is attached to a disk of 120-mm radius. The disk and drum have a total mass of 6 kg and a combined radius of gyration of 90 mm. A cord is attached as shown and pulled with a force P of magnitude 20 N. The disk rolls without sliding. Determine the...

Hello, I'm designing a machine as a final assignment for my internship. It's a machine that wraps SS tubing around a cylinder, making coils. While trying to figure out how much torque I'd need to rotate the cylinder I found that I'm really in the dark on the subject (the teacher I had didn't...

Homework Statement An Atwood machine is a rope that passes over a pulley with a block attached to each end of the rope so that the blocks are not in contact with the floor. The frictionless axle of the pulley is oriented horizontally, and the rope is vertical save where it makes contact with...

A friend of mine posed a question to me the other day and I can't seem to wrap my head around it. He's working with an electric stepper motor to turn a large thin disk, but he can't be sure of the torque required because to find the torque he needs the moment of inertia and the angular...

1. The problem statement, all variables, and given/known data Joe is painting the floor of his basement using a paint roller. A roller has a mass of 2.4kg and a radius of 3.8cm. In rolling the roller across the floor, Joe applies a force F= 16N at an angle of 35 degrees. What is the magnitude if...

Homework Statement an object starts from rest and has a final angular velocity of 6 rad/s. the object makes 2 complete revolutions. find the object's angular acceleration. Homework Equations wf^2=wi^2+2αd The Attempt at a Solution Not sure what to do with the revolutions, would it take act as...

In my textbook.In some question gives me angular speed as ( )rev/s.I know that its the frequency (f).But some questions It says angular velocity and says rad/s. Interesting thing happens when the textbook says in angular speed and I use f and then using w=2πf and then continue I get wrong...

Homework Statement A mass of 0.5 kg is suspended from a flywheel as shown in FIGURE 2. If the mass is released from rest and falls a distance of 0.5 m in 1.5 s. Mass of wheel: 3kg Outside rad. of gyration of wheel: 300mm Radius of gyration: 212mm calculate: (a) The linear acceleration of the...

Homework Statement “A bicycle wheel is mounted as in the lab and as shown to the right. This wheel has a mass of 6.55 kg, a radius of R = 38.0 cm, and is in the shape of a ring. A mass M = 1.85 kg is attached to the end of a string which is wrapped around an inner hub which has a radius r =...

Homework Statement [/B] A thin, uniform, 3.8kg bar, 80cm long has two 2.5 kg balls glued on at either end. It is supported horizontally by a thin, horizontal, frictionless axle passing through its centers and perpendicular to the bar. Suddenly the right hand ball becomes detached and falls off...

Homework Statement A record player rotates normally at a rate of 18 rev/m. It takes 70 seconds for it to slow down to a stop when you turn it off. Homework Equations Calculate the magnitude of its angular acceleration. The Attempt at a Solution answer key says the correct answer should be...

For Q11(b), what is the relation between the angular acceleration ##\alpha## of the bottom right cylinder and its horizontal acceleration ##a_x##? I get ##\alpha=\frac{a_x}{\sqrt{3}R}##, which is half the given answer (7.84) below. After the bottom right cylinder rolls around the top cylinder...

Homework Statement To lower himself from a balcony an 80kg stuntman grabs a rope connected to a 400kg cylinder with a 1.2m diameter that is free to rotate about its axis of symmetry. What is the stuntman's acceleration as he falls? Homework Equations I missed this on a homework assignment. I...

Homework Statement At a fair, Hank and Finn play with a horizontal 5.4 m long bar able to rotate about a pole going through its exact center. Hank pushes with 32 N at one end of the bar and Finn pushes with 18 N in the opposite direction at the other end. (Assume both forces are always...

Homework Statement I was in lab and we used a mass hanger and disk and plate attached to pulley to and a motion sensor to measure moment of inertia. Angular acceleration was recorded along with other values such as linear velocity and position and all that. The question is: the hanging mass...

Homework Statement Assume no friction for 1 - 6 1. Draw a free body diagram of the fly wheel (from above), and a free body diagram of the weight (from side). 2. What force appears in both diagrams? 3. What is the relationship between the torque on the flywheel and the tension in the string...

In the image above, a centroid with radius 1 is depicted. F1 is pointing directly at point A (which is the center of the circle), and F2 is pointing directly at point B. The radius for finding the torque would be the perpendicular between the center of the object and the force vector, so r1...

Homework Statement https://holland.pk/uptow/i4/ae8d3da6c3ce3cad10eb98dd3208a955.png Homework Equations τ=I⋅α The Attempt at a Solution I want to discuss in part (a) of the question Tension in 5 kg block string=mg=5*9.8=49N Taking moment at the pivot, a net torque acting on 15 kg post is...

Homework Statement In the mechanism shown below, the angular velocity of link 2 is 17 rad/s CW, constant. Find the angular velocity (magnitude and direction) of link 3. The distance between A and C is 109 mm, the length of link 3 is 125 mm, and θ= 111°. Note: B is a pin-slider In the...

In 1-dimensions, the final orientation after undergoing constant angular acceleration is: \theta_f = \theta_0 + \omega_0 t + 0.5 \alpha t^2 What is an analogous equation in the 3D case? In other words, if I know the initial orientation (say, as a quaternion), angular velocity (as a 3-vector...

Is this a legitimate equation? θ'' = − g⁄R sin θ Source: ftp://www.myphysicslab.com/pendulum1.html ftp://www.myphysicslab.com/images/pendulum_2.gif The pendulum is modeled as a point mass at the end of a massless rod. We define the following variables: θ = angle of pendulum (0=vertical) R =...

Homework Statement A sprinter runs the curve of this 200 m in 12.96 s. Assume he ran in a lane which makes a semicircle (r = 36.8 m) for the first part of the race. At 3.36 s into the race his speed is 5.1 m/s. At 7.6 s into the race his speed is 9.6 m/s. His speed after the curve was 11.1 m/s...

Homework Statement Counter clockwise is positive, right is positive and up is positive. My problem statement: When I use the formula ag = alfa*r do I have to take signs into account? Or is this formula just for the magnitude and will the signs be already taken into account in other equations...

Homework Statement The absolute angle of the thigh has the following angular velocities during the support phase of walking. Calculate the angular acceleration at time 0.02s in rad/s and in deg/s Time (s) Angular Velocity (rad/s) 0 s ----...

Homework Statement [/B] A mass of 6.1 kg tied to a string is wrapped around a disk as shown. If the disk has a mass of 8.2 kg and a radius of 2.3 m, how fast will the disk be rotating when the weight has fallen 7.4 m and was released from rest? Homework Equations Θ = S/R = x/R Θ = 0.5 α t^2 τ...

Homework Statement I was checking my work and Chegg uses the equations differently. Can somebody tell me why? Maybe I'm misunderstanding how/why to use the equation I chose. Homework Equations They say aB = -ω2ABRB/Ai I used aB = aA + αk x r - ω2rB/A The Attempt at a Solution So obviously...

Homework Statement An object of moment of inertia I is initially at rest. a net torque T accelerates the object to angular velocity omega in time t. The power with which the object is accelerated is? The right answer apparently is [ I * omega^2 ] / [2 * t]. Could anyone please explain why...

Homework Statement This is not really a question on how to solve the problem, I'm just trying to get clarification on something. For angular acceleration, α, can someone explain to me what αz is? And why does αz = α / R = αy? I understand the rest of the problem, I just don't understand...

Homework Statement A 30 kg wheel has a center of mass 0.1 m left from the center of the wheel and radius of gyration KG = 0.15 m. Find the angular acceleration if the wheel is originally at rest. The radius of the wheel is 0.25m. Homework Equations I=mk^2 T=f*d M=I*a Fn acting bottom in Y...

Homework Statement He is running around a running track training for a 400m race. His velocity is 5.11m/s around the circular end of the track, which has a radius of 31.8m. I'm trying to find his acceleration which I know is 0.821ms-2 but I can't find out how to get it. Homework Equations v=rω...

Homework Statement http://pho.to/A7jM2 Homework EquationsThe Attempt at a Solution My question is why the answer of question 15.258 (a) about the angular acceleration of rod BD isn't correct. I used the realtion of tan(25) in the end of the solution.

Homework Statement If a bike wheel rotates 9.4 times while slowing down to a stop from an initial angular velocity of 8.1 rad/s, what is the magnitude of the angular acceleration in rad/s/s Homework Equations α = at / r α = ω / t α = Θ / t^2 ω = Θ / t ω = v / r Θ = ω t + 0.5 α t^2 v final = v...

Homework Statement A car is traveling at 27.8 m/s, it undergoes a negative acceleration of 2.6 m/s/s when the brakes are applied. How many revolutions will the tires go through before the car comes to a stop if the wheels each have a radius of 1.0 m? Homework Equations α = at / r...

For the rotation of a rigid body about a fixed axis z the following holds. $$\vec{\tau_z}=\frac{d\vec{L_z}}{dt}= I_z \vec{\alpha} \tag{1}$$ Where \vec{\tau_z} is the component parallel to the axis z of a torque \vec{\tau} exerted in the body; \vec{L_z} is the component parallel to the rotation...