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Angular Momentum

Miscellaneous physics question

1. Competitive divers pull their limbs in a curl up their bodies when they do flips. Just before entering the water, they fully extend their limbs to enter straight down. Explain the effect of both actions on their angular velocity. What is the effect of these actions on their angular momentum? 2. What is the final velocity

Rotating bodies and angular momentum : Rolling objects and moment of inertia

A sphere of radius mass M and moment of inertia I rolls down a slope that is inclined at an angle phi to the horizontal. The sphere starts from rest and rolls without slipping a distance L down the slope. Choose coordinates x and theta as shown. a) Write down a relationship between x and theta. Please see the attached fi

Rotating bodies and angular momentum : Rolling objects and moment of inertia

A sphere of radius mass M and moment of inertia I rolls down a slope that is inclined at an angle phi to the horizontal. The sphere starts from rest and rolls without slipping a distance L down the slope. Choose coordinates x and theta as shown. a) Write down a relationship between x and theta. (Answer x =R*theta) b) Wri

Tension, Force, Momentum, Velocity, Temperature, Energy

1. A 9kg hanging weight is connected to a string over a pulley to a 5kg block that is sliding on a flat table. If the coefficient of kinetic friction is 0.15, find the tension in the string. 2. A 50kg ice skater is moving at 5m/s when she grabs the loose end of a rope, the opposite end of which is tied to a pole. She then mo

Rotational Dynamics Simple Harmonic Motion

A woman stands at the center of a platform. The woman and the platform rotate with an angular speed of 1.30 rad/s. Friction is negligible. Her arms are outstretched, and she is holding a dumbbell in each hand. In this position the total moment of inertia of the rotating system (platform, woman, and dumbbells) is 6.66 kg·m2. By

Calculating velocity and angular velocity

Please help with the following problem. Provide step by step calculations fo reach. A uniform cylinder (A) has a mass ( m = 3 kg ), radius ( r = 150 mm ), and can roll without sliding on a cart ( C ) of mass ( M = 5 kg ). Cylinder (A) is attached to a spring (AB) of stiffness (constant) k = 100 N/m as shown (attached). The s

Fnd the rate of rotation of the collapsed star

A star rotates about its axis through a diameter once in 50 days. At the end of its life, the star collapses to one-hundreth of its original diameter. The rate of rotation of the collapsed star will be: a. 0.02 rotaions per day b. 20 rotaions per day c. 2 rotaions per day d. 200 roations per day

Angular Velocity and Distance Problems

A 1.62 oz golf ball with a 1.70 in. diameter is hit by a club at point P. Velocity magnitude of the ball's center of mass is 180 ft/s after the impact. What is the angular velocity of the ball? (h = 0.2 in.) A 1 oz. bullet with a horizontal velocity of 350 ft/s strikes a circular disk. The bullet is embedded into the disk aft

Rotation of a Diver

A diver can change her rate of rotation in the air by "tucking" her head in and bending her knees. Lets assume that when she is stretched out straight she is rotating at 1 revolution per second. Now she goes into the "bend and tuck", effectively shortening the length of her body in half. What will her roation be now? a. 5Hz

Rotational Motion and Angular Momentum

Two lightweight rods L = 19.6cm in length are mounted perpendicular to a vertical axle and at 180 degrees to each other (see figure attached). At the end of each rod is a m = 640 g mass. The rods are spaced h = 39.6cm apart along the axle. The axle rotates at 28.0rad/s such that the angular velocity vector points upward (+). W

Running on circular platform

Suppose a 60kg person stands at the edge of a 6.0m diameter circular platform, which is mounted on frictionless bearings and has a moment of inertia of 1800kgm^2. The platform and runner are initially at rest. Calculate the angular velocity of the platform if the runner begins to run 4.2m/s.

Rotating a Professor on a Turntable

Hi I need you help for two questions. 1. A professor steps onto a stationary turntable while holding a rotating bicycle wheel that is rotating with an angular velocity of 15 rad/s pointing upward. The wheels axis of rotation goes through the axis of the turntable. The rotational inertia of the wheel is 1.5 kg m^2 and the co

Mechanics: Dynamics (Translational and rotational motion).

1. Two equal weights of mass M each are connected by a cord passing over a frictionless pulley of mass mp and radius r. An additional weight of mass m is placed on one of the weights of mass M. Derive the expression for: a) system acceleration a; b) cord tensions. 2. A helicopter rotor blade can be considered a long thin

Magnitude of Angular Momentum

1. A car of mass 1000 kg moves with a speed of 50 m/s on a circular track of radius 100 m. What is the magnitude of its angular momentum (in kg.m^2/s) relative to the center of the racetrack? 2. A Body oscillates with simple harmonic motion along the x-axis. Its displacement varies with time according to the equation x=5 sin

Angular momentum and stationary distance after a collision

A thin uniform rod of length .6m and mass M is rotating horizontally at 79.0 rad/s counterclockwise about an axis through its center. A particle of mass M/3 and speed 38.5 m/s hits the rod and sticks. The particle's path is perpendicular to the rod at the instant of the hit, at a distance d from the rod's center. At what valu

Angular momentum of a space station

A space station is constructed in the shape of a hollow ring of mass 5.00 x 10^4 kg. Members of the crew walk on a deck formed by the inner surface of the outer cylindrical wall of the ring, with radius of 100m. At rest when constructed, the ring is set rotating around its axis so that the people inside experience an effectiv

Angular momentum of a rotating rigid object

A uniform solid sphere of radius 0.500 m and mass of 15.0kg turns counterclockwise about a vertical axis through its center. Find its vector angular momentum when its angular speed is 3.00 rad/s. I think I have worked this problem correctly. (See attachment) Please check my answer and confirm if in correct please point ou

Basic Physics: Force and Friction

The 3.20kg, 38.0cm diameter disk in the figure is spinning at 350 rpm. How much friction force must the brake apply to the rim to bring the disk to a halt in 2.40 seconds? (Please see attachment for diagram.)

Mechanics, rotation, angular deceleration. Part 3

A flywheel initially rotating at a speed of 800 rev/min, is brought to rest with uniform angular deceleration in 6's c. At what time will both the radial and tangential components of acceleration be equal in magnitude?

Angular Velocity of a Block on a Heated Spinning Rod

A 1.10 m-long massless rod is pivoted at one end and swings around in a circle on a frictionless table. A block with a hole through the center can slide in and out along the rod. Initially, a small piece of wax holds the block 10.0 cm from the pivot. The block is spun at 50.0 rpm, then the temperature of the rod is slowly increa

Bohr Quantium Condition

A particle of mass m is attracted to the origin by a force proportional to the distance from the origin F = -kr. Assume that it moves in circular orbit of radius r. a) Use Newton's law to show that its kinetic energy 1/2mv^2 equals its potential energy 1/2kr^2. b) Use Bohr quantum condition on the angular momentum (L = nh

Angular momentum of a projectile

A particle of mass M is shot with an initial velocity Vi and makes an angle theta with the horizontal. The particle moves in the gravitational field of the earth. Find the angular momentum of the particle about the origin when the particle is (a) at the highest point of the trajectory and (b) just about to hit the ground.

Conservation of angular momentum when a system changes configuration.

A uniform cylinder, mass M= 12 kg, radius R= .36 m, is initially rotating about a vertical axis through its center at angular velocity wo= 6.6 rad/sec. Now two small (point masses), each of mass m= 2 kg, are dropped onto and stick to the cylinder, each at distance r= .24 m from the axis. SEE ATTACHMENT for diagram. Find wf, t

Moment of Inertia for Figure Skater

A figure skater during her finale can increase her rotation rate from an initial rate of 1.12 revolutions every 1.88 s to a final rate of 3.15 revolutions per second. If her initial moment of inertia was 4.73 kg* m2, what is her final moment of inertia?