Rotational kinetic energy Definition and 135 Threads

Homework Statement What is the Kinetic Energy of the Earth Orbiting Around the Sun in Joules? Homework Equations E rotation = (1/2)* I * w^2 where I = moment of Inertia where w = angular velocity The Attempt at a Solution Well, this is my predicament: I don't know whether...

Hello: can someone help me with the following? A rigid assembly of a thin hoop (of mass m and radius R of 0.15m) positioned on top of a thin radial rod (of mass m and length L = 2.0 R). (So imagine a circle on top of a stick, whereby if you extend the stick you will hit the center of the...

Homework Statement A sphere with a 3 kg * m^2 moment of inertia about an axis through its center has its angular velocity changed by 4 rad/s owing to a 2 N*m torque applied about that axis for 6s. If its initial angular velocity is 10 rad/s, the change in its rotational kinetic energy in J...

A 30-cm diameter circular saw blade has a mass of 0.9 kg distributed uniformly in a disc. (a) What is its rotational kinetic energy when it is operating at 4000 rpm? (b) What average power must be applied to bring the blade from rest to its operating 4000 rpm? Just making sure I'm doing...

Homework Statement A 32.0 kg wheel, essentially a thin hoop with r=1.20 m is rotating at 280 rev/min. It must be brought to stop in 15.0 s. How much work must be done to stop it? Homework Equations/The Attempt at a Solution I=mr^2=46.08 kg*m^2 W=(1/2)I\omegaf^2 - (1/2)I\omegai^2...

Is there an amazing way I can demonstrate Rotational Kinetic Energy in a classroom? It's for a presentation and I've looked and thought about some experiments but they involve Angular Momentum which another group has to present/explain. Sorry if this is in the wrong section, it's my first...

Homework Statement Engineers are designing a system by which a falling mass {m} imparts kinetic energy to a rotating uniform drum to which it is attached by thin, very light wire wrapped around the rim of the drum ( View Figure ). There is no appreciable friction in the axle of the drum, and...

Homework Statement The three 300 g masses in the figure are connected by massless, rigid rods to form a triangle. What is the triangle's rotational kinetic energy if it rotates at 8.00 revolutions per s about an axis through the center? Values given: Mass of each ball at the corner...

[SOLVED] Rotational Kinetic Energy Homework Statement A solid cylinder of mass 14.0 kg rolls without slipping on a horizontal surface. (a) At the instant its center of mass has a speed of 11.0 m/s, determine the translational kinetic energy of its center of mass. Homework Equations...

A quote from the 'Light-dragging effects' section from wikipedia states- "Under general relativity, the rotation of a body gives it an additional gravitational attraction due to its kinetic energy.." Based on this, does rotational kinetic energy contribute the gravity of an object...

1.A wooden block of mass M resting on a frictionless, horizontal surface is attached to a rigid rod of length and of negligible mass. The rod is pivoted at the other end. A bullet of mass m traveling parallel to the horizontal surface and perpendicular to the rod with speed v hits the block and...

A bicycle has wheels of radius 0.33 m. Each wheel has a rotational inertia of 0.082 kg* m2 about its axle. The total mass of the bicycle including the wheels and the rider is 74 kg. When coasting at constant speed, what fraction of the total kinetic energy of the bicycle (including rider) is the...

[SOLVED] Rotational Kinetic Energy and distribution of diatomic molecules a) Calculate the total rotational kinetic energy of the molecules in 1.00 mol of a diatomic gas at 300 K. b) Calculate the moment of inertia of an oxygen molecule (O2) for rotation about either the x- or y-axis shown...

Homework Statement A solid sphere of mass 4 kg rolls w/o slipping UP an incline with an angle of 30 degrees. the radius of the sphere is 0.5 m and its moment of Inertia is I = 2/5(m)R^2. At the bottom of the incline the center of mass of the sphere has a translational speed of 5 m/s. a)...

The marble rolls down a track and around a loop-the-loop of radius R. The marble has mass m and radius r (see picture). What minimum height h must the track have for the marble to make it around the loop-the-loop without falling off? This is driving me nuts. I know that the total mechanical...

Homework Statement A bicycle has wheels of radius 0.29 m. Each wheel has a rotational inertia of 0.091 kg·m^2 about its axle. The total mass of the bicycle including the wheels and the rider is 79 kg. When coasting at constant speed, what fraction of the total kinetic energy of the bicycle...

Homework Statement A horizontal 813 N merry-go-round of radius 1.28 m is started from rest by a constant horizontal force of 66 N applied tangentially to the merry-go-round. The acceleration of gravity is 9.8 m/s^2. Assume it is a solid cylinder. Find the kinetic energy of the merry-go-round...

Homework Statement A bicycle has wheels of radius 0.3 m. Each wheel has a rotational inertia of 0.08 kg* m2 about its axle. The total mass of the bicycle including the wheels and the rider is 74 kg. When coasting at constant speed, what fraction of the total kinetic energy of the bicycle...

Homework Statement Suppose a solid cylindrical flywheel has a mass of 200 kg and a radius of 0.8 m and rotates at a rate of 15,000 revolutions per minute. If you were able to convert all of its rotational kinetic energy into making you run, how fast would you be going? (Assume your mass is...

how do u define rotational kinetic energy when the body is rotting about more than one axis. as an example take a ball that ia rotaing about an axis passing through the centre of ineria whiloe the centre itself rotates in an axis perpendicular to this

Hi, on the net I found some equation, and would like to know if they are correct ones. http://www.upei.ca/~physics/p261/projects/flywheel1/flywheel1.htm http://hyperphysics.phy-astr.gsu.edu/hbase/rke.html Physics: Stored energy = sum of kinetic energy of individual mass...

Homework Statement A horizontal 800.0 N merry-go-round with a radius of 1.5 m is started from rest by a constant horizontal force of 50.0 N applied tangentially to the merry-go- round. Find the kinetic energy of the merry-go-round after 3.0 s. Assume it is a solid cylinder.Homework...

Hello. I'm an intro physics student, who needs help with physics problem, because my graduate student refuses to help anybody in my class anyway... here is my first question on rotational kinetic energy 1) "A uniform disk of mass M and radius R can rotate freely about a horizontal axis...

Hi there, I am currently in the middle of studying for an exam in a few weeks time. I would appreciate it if someone could just have a quick look over the following details below and see if I am along the right lines. 1. A solid wheel of mass 15Kg is at the top of a slope 1in4. The slope...

The puck in Figure P8.51 has a mass of 0.120 kg. Its original distance from the center of rotation is 40.0 cm, and it moves with a speed of 85.0 cm/s. The string is pulled downward 15.0 cm through the hole in the frictionless table. Determine the work done on the puck. (Hint: Consider the change...

A 2.4 kg cylinder (radius = 0.09 m, length = 0.50 m) is released from rest at the top of a ramp and allowed to roll without slipping. The ramp is 0.74 m high and 5.0 m long. What is its rotational kinetic energy? I just wanted to make sure that I was on the right track... I=2/5 mr^2...

A 50kg rider on a moped of mass 75kg is traveling with a speed of 20 m/s. Each of the two wheels of the moped has a radius of 0.2m and a moment of inertia of 0.2 kg*m^2. What is the total rotational kinetic energy of teh wheels? KEr = 1/2Iw^2 = 1/2(.02)(20)^2 = 4 Two wheels = 2...

ok, so a thread with hanging mass at the end is wrapped around a disk. the disk is dropped and mass is released. how do you find the kinetic energy of the weight at a given time/distance fallen from the disk? I'm not sure to whether use rotational kinetic energy or linear kinetic energy... all...

I have a question about this question that I hope someone can answer. QUESTION: "A student on a piano stool rotates freely with an angular speed of 29.5rps. The student holds a 1.25 kg mass in each outstretched arm, .759m from the axis of rotation. The combined moment of Inertia of the...

Hi Please I would like to have some help with this problem: A cylinder of mass .2 kg rolls without slipping down an inclined plane of 15 degree. What is its rotational kinetic energy after it rolls 80cm? I tried the formula W=Kf - Ko but It does not bring me to the solution. Thank you for...

Please help me get this, it's due tonigh tonight on webassign. The question is: A 3.30 m long pole is balanced vertically on its tip. It is given a tiny push. What will be the speed of the upper end of the pole just before it hits the ground? Assume the lower end does not slip. I know to...

Hi, I am rather perplexed by the solution to the following problem. Particles of mass M1 and M3 are fastened to the ends of a light rod having a length l. A bead of mass M2 is free to slide along the rod between M1 and M3. Point p is the center of mass of M1 and M3, not including...

I'm afraid I need some help on this one. We are studying rotational dynamics and I read in my textbook, the explanation of a common classroom deonstration. A person sits on a rotating stool and holds heavy weights in their outstretched hands. Someone sets the individual into rotational motion...

In a crude model of a rotating diatomic molecule of chlorine (Cl2), the two Cl atoms are 2.00e-10 m apart and rotate about their center of mass with angular speed w = 1.40e12 rad/s. What is the rotational kinetic energy of one molecule of Cl2, which has a molar mass of 70.0 g/mol? >> I...

Please, help with rotating rigid body problem I am kind of stuck with this problem. Any takers? A large, cylindrical roll of tissue paper of initial radius R lies on a long, horizontal surface with the outside end of the paper nailed to the surface. The roll is given a slight shove (V...