# Physics - Rotational Mechanics

73,759 results

### Maths, mechanics, stat

A molecule has a rotational inertia 14000amupmsquare spining at an angular speed of 4. 30x10exponent12 radpersecond a) express the rotational inertia in kgmsq b)calculate rotational kinetic energy in EV.

### ap physics

Determine the change in rotational kinetic energy when the rotational velocity of the turntable of a stereo system increases from 0 to 33 rpm. Its rotational inertia is 6.8×10−3kg⋅m2 .

### physics

Determine the change in rotational kinetic energy when the rotational velocity of the turntable of a stereo system increases from 0 to 33 rpm. Its rotational inertia is 6.8×10−3kg⋅m2 .

### physics

What kind of motion does a constant, non zero torgue produce on an object mounted on an axle: choices constant rotational speed, constant rotational acceleration, increasing rotational acceleration or decreasing rotational acceleration.

### Physics

Rotational Inertia- Particle 1: m=50g x=2 cm y=2 cm P 2: m=25 x=0 y=4 P 3: m=25 x=-3 y=-3 P 4: m=30 x=-e y=4 The question says to find the rotational inertia of the collection about the x, y, and 7 axis in g/cm^2, then suppose the x axis rotational inertia is A and the y axis ...

### physics

A ballet student with her arms and a leg extended spins with an initial rotational speed of 0.90rev/s . As she draws her arms and leg in toward her body, her rotational inertia becomes 0.80 kg⋅m2 and her rotational velocity is 4.1rev/s . Determine her initial rotational ...

### physics

A circle is cut out of a uniform piece of plywood. How does the rotational inertia measured around a point on its outer edge compare with the rotational inertia about its central axis? a. The two rotational inertias are the same. b. The rotational inertia about its edge is ...

### ap physics

A 10-kg disk-shaped flywheel of radius 9.0 cm rotates with a rotational speed of 320 rad/s. Determine the rotational momentum of the flywheel. With what magnitude rotational speed must a 10-kg solid sphere of 9.0 cm radius rotate to have the same rotational momentum as the ...

### physics

A 10-kg disk-shaped flywheel of radius 9.0 cm rotates with a rotational speed of 320 rad/s. Determine the rotational momentum of the flywheel. With what magnitude rotational speed must a 10-kg solid sphere of 9.0 cm radius rotate to have the same rotational momentum as the ...

### Physics

A diver jumps off a dving board and does a twisting manuever. In the midst of his jump in the air, the diver cannot change his a. Rotational Energy b. Rotational Speed c. Rotational Inertia d. Angular momentum I say d just want to make sure

### physics

A ballet student with her arms and a leg extended spins with an initial rotational speed of 1.2 rev/s . As she draws her arms and leg in toward her body, her rotational inertia becomes 0.80 kg⋅m2 and her rotational velocity is 3.9 rev/s .Determine her initial rotational ...

### physics

A trapeze artist sailing through the air rotates with a rotational speed of 0.9·rev/s. If she contracts to reduce her rotational inertia to one sixth of what it was, what will her new rotational speed be? _____ rev/s? Can she completely stop her rotation while still airborne...

### Physics C: Mechanics

A yo-yo has a rotational inertia of 760 g·cm2 and a mass of 200 g. Its axle radius is 4.0 mm, and its string is 100 cm long. The yo-yo rolls from rest down to the end of the string. (a) What is the magnitude of its linear acceleration? cm/s2 (b) How long does it take to reach...

### Physics

What equation is the rotational equilvalent of newton's law ? give the meaning of each symbol and state which rotational quantites are analogous to which linear quantities.

### physics

A heavy flywheel rotating on its central axis is slowing down because of friction on its bearings. At the end of the first minute of slowing, its rotational speed is 0.90 of its intial rotational speed of 250 rev/min. Assuming a constant rotational acceleration, find its ...

### Physics-Mechanics

horizontal surface. The block is connected by a cord passing over a pulley to another block of mass 5.53 kg which hangs in the air, as shown on the following picture. Assume the cord to be light (massless and weightless) and unstretchable and the pulley to have no friction and...

### Physics

A 21-kg child starts at the center of a playground merry-go-round that has a radius of 3.5 m and rotational inertia of 500 kg⋅m2 and walks out to the edge. The merry-go-round has a rotational speed of 0.20 s−1 when she is at the center. What is its rotational speed...

### physics

If the rotational speed of a CD changes from 550 rpm to 200 rpm as it plays 30 minutes of music, what is the CD's average rotational acceleration?

### Physics-help please!

A net torque of 54 N.m is applied to a disk with a rotational inertia of 13.2 kg.m2 What is the rotational acceleration of the disk?

### Physics

Did Einstein support quantum mechanics as being fundamental physics, or did he think quantum mechanics was inconclusive?

### physics

What is the rotational kinetic energy of a planet about its spin axis? Model the planet as a uniform sphere of radius 6000 km, and mass 6.21 x 10^24 kg. Assume it has a rotational period of 24.0 h.

### Physics

If the electron in a hydrogen atom obeyed classical mechanics instead of quantum mechanics, would it emit a continuous spectrum or a line spectrum?

### Physics

A merry-go-round in the park has a radius of 1.8 m and a rotational inertia of 900 kgm^2. A child pushes the merry-go-round with a constant force of 80 N applied at the edge and parallel to the edge. A frictional torque of 12 Nm acts at the axle of the merry-go-round. a. What ...

### physics

A turntable turning at rotational speed 21rpm stops in 50s when turned off. The turntable's rotational inertia is 1.2×10−2kg⋅m2. a)Determine the magnitude of the resistive torque that slows the turntable.

### Physics

A wheel with radius R, mass m, and rotational inertia I rolls without slipping across the ground. If its translational kinetic energy is E, what is its rotational kinetic energy?

### Physics

At the start of your throw of a 5.6-kg bowling ball, your arm is straight behind you and horizontal (Figure 1) . Your arm is 0.64 m long, has a rotational inertia of 0.48 kg⋅m2 and has a mass of 3.5 kg with its center of mass 0.28 m from your shoulder joint. Determine ...

### physics

A uniform disk with a mass of 800 g and radius 17.0 cm is rotating on frictionless bearings with an rotational speed of 18.0 Hz when Jill drops a 130 g clod of clay on a point 7.10 cm from the center of the disk, where it sticks. What is the new rotational speed of the disk?

### physics

Consider a 8·kg rod with a length of 0.6·m and rotating about an axis passing through its center. (a) What is its rotational inertia? (B) Suppose the rod is rotating counterclockwise and speeding up with a rotational acceleration of 7·rad/s2. What is the net torque acting ...

### Physics

The rotational inertia of a collapsing star changes to one third its initial value while conserving angular momentum. What is the ratio of the new rotational kinetic energy to the initial kinetic energy?

### Physics

A meter stick has mass 39 g, and has a pivot placed at the center at the 50 cm mark. A mass of m1 is place at the 5 cm mark. Another mass of 10 g is placed at the 70 cm mark. What mass m in grams has to be placed at the 80 cm mark to create translational and rotational ...

### Physics

A mass of 1.0 kg is located at the end of a very light and rigid rod 44 cm in length. The rod is rotating about an axis at its opposite end with a rotational velocity of 3 rad/s. (a) What is the rotational inertia of the system? kg · m2 (b) What is the angular momentum of the...

### Physics

An ice skater, has a rotational inertia of I = 4 kg m2, and spins at 2 rad/sec. She then changes her rotational inertia to 2 kg m2. What is her final angular velocity? a. 4 rad/s b. 2 rad/s c. 2.8 rad/s d. 8 rad/s The answer must be A then right.

### Physics

A 70 kg student holds a 2.0 kg mass in each hand and is sitting on a stool that can rotate freely about a vertical axis. With the masses held at arm’s length (0.9 m) the student is set spinning at 1.2 revolutions per second. a. If we approximate the student as a uniform ...

### Physics

An ice skater, has a rotational inertia of I = 4 kg m2, and spins at 2 rad/sec. She then changes her rotational inertia to 2 kg m2. What is her final angular velocity? a. 4 rad/s b. 2 rad/s c. 2.8 rad/s d. 8 rad/s I say B, am i right?

### Physics

The rotational velocity of a merry-go-round increases at a constant rate from 1 rad/s to 2.1 rad/s in a time of 5.8 s. What is the rotational acceleration of the merry-go-round?

### mechanics

Find the total kinetic energy of a 1500 g wheel, 700 mm in diameter, rolling across a level surface at 650 rpm. Assume that the wheel can be considered as a hoop. (b) For the wheel in part (a), calculate the torque required to decrease its rotational speed from 400 rpm to rest...

### PHYSICS

The masses and coordinates of four particles are as follows: 40 g, x = -4.0 cm, y = 5.0 cm; 30 g, x = 5, y = 0.0 cm; 40 g, x = –5.0 cm, y = 3.0 cm; 20 g, x = 3.0 cm, y = 2.0 cm. What are the rotational inertias of this collection about the (a) x, (b) y, and (c) z axes? >&...

### rotational mechanics

a thin rod of length 2R and mass M is standing vertically on a perfectly smooth floor. the state of equilibrium in which the rod at rest is unstable and the rod falls. FInd the trajectories that the various points of rod describe and velocity with which the upper end of rod ...

### Physics C: Mechanics

A 1.00 kg mass is attached to a string wrapped around a cylinder of radius 0.05m. Two masses are connected with a rod and attached to the end of the cylinder, perpendicular to its axis. as the mass falls from rest the rotating contraption spins through 12 pi radians in 1.2 ...

### Physics

An ice skater, hasa rotational inertia of I = 4 kg m2, and spins at 2 rad/sec. Her rotational inertia then undergoes a change to 2 kg m2. Which of the following is true? a. Her angular momentum remains the same b. Her angular velocity increases c. Her kinetic energy increases ...

### Physics

create a graph with your data of rotational speed vs radius. independent variable goes on x axis. which is x axis and which is y axis out of radius and rotational speed

### Physics

A disk lying on the XY plane rinitially roates counter-clockwise with a rotational speed of w0. After a time interval rt, the rotational speed has changed to wf moving in the clockwise direction. The average torque during this time interval is which of the following?

### Physics help!

Suppose a revolving door at the bamk is spinning around once every 5 seconds. As you walk through, you push on the door for 2 seconds, which increases the rotational speed so that it rotates once a second. What was the rotational acceleration due to your push?

### Physics PLEASE HELP!

Suppose a revolving door at the bamk is spinning around once every 5 seconds. As you walk through, you push on the door for 2 seconds, which increases the rotational speed so that it rotates once a second. What was the rotational acceleration due to your push?

### PHYSICS PLEASEEEE HELP ME

Suppose a revolving door at the bank is spinning around once every 5 seconds. As you walk through, you push on the door for 2 seconds, which increases that rotational speed so that it rotates once a second. What was the Rotational acceleration due to your push?

### physics

The speedometer on an automobile measures the rotational speed of the axle and converts that to a linear speed of the car, assuming the car has 0.62-m-diameter tires. What is the rotational speed of the axle when the car is traveling at 26m/s ?

### mechanics/motion

Can someone help me with mechanics. I need to check my answers

### Physics - Rotational Motion

(#1.) A top starting from 40 rad/s takes 200 rad to stop. What is its rotational acceleration? (a constant) (#2.) A stationary 100 Kg circular object (r= 0.20 m) is on a 35 degree incline. The coefficient of rolling friction between the block and the incline is 0.01. If it ...

### physics

The uniform solid block in Fig. 11-36 has a mass of M = 5.60 kg and edge lengths a = 17.5 cm, b = 39.5 cm, and c = 2.85 cm. Calculate its rotational inertia about an axis through one corner and perpendicular to the large faces I know you have to find the center of mass to get ...

### physics

Find the rotational kinetic energy of the earth about the sun due to its orbit about the sun. The mass of the earth M is 6 x 1024 kg, the orbital radius r is 1.5 x 1011 m and the rotational period T is 1 year. Treat the earth as a point mass in this problem.

### physics

Find the rotational kinetic energy of the earth about the sun due to its orbit about the sun. The mass of the earth M is 6 x 1024 kg, the orbital radius r is 1.5 x 1011 m and the rotational period T is 1 year. Treat the earth as a point mass in this problem

### Physics

it says create a graph from our data. rotational speed vs force. i know that independent variable goes on the x axis. but out of rotational speed and force which goes on the x axis and which goes on the y?

### Physics

it says create a graph from our data. rotational speed vs force. i know that independent variable goes on the x axis. but out of rotational speed and force which goes on the x axis and which goes on the y?

### physics

find the rotational kinetic energy of the earth about the sun due to its orbital about the sun. The mass of the each M is 6 X 10^24 kg, the orbital radius r is 1.5 X 10^11 m and the rotational period T is 1 year. Hint, treat the earth as a point mass in this problem.

### Physics

A lawn mower has a flat, rod-shaped steel blade that rotates about its center. The mass of the blade is 0.65kg and its length is 0.55m. What is the rotational energy of the blade at its operating angular speed of 3450 rpm? If all of the rotational kinetic energy of the blade ...

### English

Over time, non-specialists are usually able to assimilate radically new scientific ideas, even though these ideas may seem strange when they are initially introduced. Such was the case with Newtonian physics; when Newton proposed his ideas regarding motion and gravitation in ...

### critical thinking

Over time, non-specialists are usually able to assimilate radically new scientific ideas, even though these ideas may seem strange when they are initially introduced. Such was the case with Newtonian physics; when Newton proposed his ideas regarding motion and gravitation in ...

### CRT205 Quiz

Over time, non-specialists are usually able to assimilate radically new scientific ideas, even though these ideas may seem strange when they are initially introduced. Such was the case with Newtonian physics; when Newton proposed his ideas regarding motion and gravitation in ...

### Critical Thinking

Over time, non-specialists are usually able to assimilate radically new scientific ideas, even though these ideas may seem strange when they are initially introduced. Such was the case with Newtonian physics; when Newton proposed his ideas regarding motion and gravitation in ...

### Critical Thinking

Over time, non-specialists are usually able to assimilate radically new scientific ideas, even though these ideas may seem strange when they are initially introduced. Such was the case with Newtonian physics; when Newton proposed his ideas regarding motion and gravitation in ...

### Physics Urgent please help

A figure skater stands on one spot on the ice(assumed frictionless) and spins around with her arms extended. When she pulls in her arms, her moment of inertia decreases to 3/4 of the initial value. Assume that her spin angular momentum is conserved. What is the ratio of her ...

### Physics

To reduce its rotational inertia, an engineer proposes drilling three holes in a large wheel of radius R. The holes are to be centered midway between the center and edge of the wheel. What should be their radii (in terms of R) if drilling the holes is to reduce the rotational ...

### physics

A wheel has a rotational velocity of 18·rad/s counterclockwise. You place you hand against the wheel and the friction between your hand and the rim stops it. (a) If it takes 4·s to stop the wheel, what is its rotational acceleration? rad/s2 (b) How far does the wheel rotate ...

### PHYSICS 1

When a pitcher throws a curve ball, the ball is given a fairly rapid spin. A 0.15 kg baseball with a radius of 3.7 cm is thrown with a linear speed of 41 m/s and an angular speed of 37 rad/s. Assume that the ball is a uniform, solid sphere. (b) Calculate how much of its ...

### physics help 4 please!

A solid disk (mass = 1 kg, R=0.5 m) is rolling across a table with a translational speed of 9 m/s. a.) What must the angular speed of the disk be? ? rad/s b.) What is the rotational KE of the disk? ? J c.) What is the total KE of the disk? ? J d.) The disk then rolls up a hill...

### phys

A disk rolls down a slope. It rotational axis is its center of mass. It is rotation at a constant angular speed making 34.0 full revolutions in a time interval of 3.30 s. 1)What is the rotational inertia of the disk if its mass is 11.7 kg, and its radius is 49.6 cm? A=1.44kmg^...

### Physics

A potter’s wheel with rotational inertia of 45 kg m2, is spinning freely at 40 rpm. The potter drops a lump of clay onto the wheel where it sticks a distance 1.2 m from the rotational axis at the wheel’s center. If the subsequent angular speed of the wheel is 32 rpm, what ...

### english: crit. thinking

Over time, non-specialists are usually able to assimilate radically new scientific ideas, even though these ideas may seem strange when they are initially introduced. Such was the case with Newtonian physics; when Newton proposed his ideas regarding motion and gravitation in ...

### math

any shape with 4 lines of symmetry and rotational order 2. A rectangle would fit that description. See http://www.icteachers.co.uk/children/sats/rotational.htm#Maths I hope this helps. Thanks for asking. i need some help on my maths and i am inbarresed to ask my teacher

### Physics - Rotational Motion

(#1.) A top starting from 40 rad/s takes 200 rad to stop. What is its rotational acceleration? (a constant) (#2.) A stationary 100 Kg circular object (r= 0.20 m) is on a 35 degree incline. The coefficient of rolling friction between the block and the incline is 0.01. If it ...

### physics

An antique carousel that’s powered by a large electric motor undergoes constant angular acceleration from rest to full rotational speed in 6 seconds. When the ride ends, a brake causes it to decelerate steadily from full rotational speed to rest in 8.9 seconds. Compare the ...

### physics

A spinning flywheel has rotational inertia I = 402.9 kgm2. Its angular velocity decreases from 20.3 rad/s to zero in 266.6 s due to friction. What is the frictional torque acting? Torque= MomentofInertia*angularacceleration. You are given the moment of inertia (you named it ...

### Calculus

Use newtons method and the function f(x)=x^2-a to derive the mechanics rule. Mechanics Rule for approaching sqrt(a), a>0, is Xn+1=1/2(Xn+a/Xn), n=1,2,3,...

### PHYSICS--SHM

A pendulum consists of a uniform disk with radius r = 10 cm and mass 545 g attached to a uniform rod with length L = 500 mm and mass 300 g. (figure: one end of the rod attach to a pivot and the other end attach to the center of the disk) (a) Calculate the rotational inertia of...

### Physics

A potter’s wheel with rotational inertia 24 kg m2 is spinning freely with no friction at 50 rpm. A piece of clay is dropped from above the wheel and sticks 0.5 m from the center of the wheel. Afterward, the rotational speed of the wheel and clay has dropped to 48 rpm. The ...

### math

At the Whistlestop Cafe, 15 of the 19 patrons are mechanics. If a sample of 8 is taken, what is the probability that exactly 5 patrons are mechanics? Round your answer to 4 decimal places.

### math

At the Whistlestop Cafe, 15 of the 19 patrons are mechanics. If a sample of 8 is taken, what is the probability that exactly 5 patrons are mechanics? Round your answer to 4 decimal places.

### Fluid Mechanics

Hello Can someone can give me good links where i can find the: 1)domestic 2)industrial applications of fluid mechanics ? Tnx a lot.

### physics

A yo-yo has a rotational inertia of 810 g·cm2 and a mass of 95 g. Its axle radius is 2.6 mm and its string is 100 cm long. The yo-yo is thrown so that its its initial speed down the string is 1.0 m/s. (a) How long does the yo-yo take to reach the end of the string? s (b) As ...

### physics

A merry-go-round in the park has a radius of 1.8 m and a rotational inertia of 900kgm^2. A child pushes the merry-go-round with a constant force of 80 N applied at the edges and parallel to the edge. A frictional torque of 12 Nm acts at the axle of the merry-go-round. a. what ...

### physics

The sweeping second hand on your wall clock is 24cm long. a)What is the rotational speed of the second hand? b)Find the translational speed of the tip of the second hand. c)Find the rotational acceleration of the second hand.

### Physics

A man stands on a freely rotating platform, as shown, holding an exercise dumbbell in each hand. With outstretched arms, his angular speed is 1.5 rad/s. After he has pulled his arms in, as shown, his angular speed is 5 rad/s. What is the ratio of his final rotational KE to his...

### physics

A merry go round in the park has a radius of 1.8 m and a rotational inertia of 900 kg-m^2. A child pushes the merry go round with a constant force of 80 N applied at the edge and parrallel to the edge. A frictional torque of 12 Nm acts at the axle of the merry go round. What ...

### Math

A car dealership employs 12 salesman and 28 mechanics. What is the ratio of salesman to mechanics?

### physics

An experimental flywheel, used to store energy and replace an automobile engine, is a solid disk of mass 202.0 kg and radius 0.35 m. (a) What is its rotational inertia? (b) When driving at 22.4 m/s (50 mph), the fully energized flywheel is rotating at an angular speed of 3160 ...

### math

how can you determine whether a design has rotational symmetry? if a design has a rotational symmetry, how many can you find the angle of roation??

### Physics

A rolling barrel with initial velocity 20 m/s encounters a hill 10m tall to slow it down 1. state where its angular speed is 0 2. state where its rotational kinetic energy will be 0 3. state where its translation kinetic energy will be 0 4. for each of the two flat surfaces ...

### Physics, Please help today

0.0100kg particles have been glued to a rod of Length L=6.00cm and negligible mass and can rotate around a perpendicular axis through point O at one end. How much work is required to change the rotational rate (a) from 0-20.0 rad/s, (b) from 20.0 rad/s to 40.0 rad/s, and (c) ...

### physics-rotational dynamics

Two astronauts, each having a mass of 75.0 kg, are connected by a 10.0 m rope of negligible mass. THey are isolated in space,orbiting their center of mass at speeds of 5.00 m/s. calculate A)magnitude of the angular momentum of the system by treating astronauts as particles and...

### Physics(Rotational Energy)

Suppose three masses are arranged as shown, connected by a rodless mass. (2 kg)-------(6 kg)--------(4 kg) 2m 3m a) If this object is free to rotate in space, about what point will it spin? b) A small mass (m=0.1 kg) drops vertically onto the2 kg mass traveling 100 m/s and ...

### ENGLISH

Over time, non-specialists are usually able to assimilate radically new scientific ideas, even though these ideas may seem strange when they are initially introduced. Such was the case with Newtonian physics; when Newton proposed his ideas regarding motion and gravitation in ...

### physics

Some special vehicles have spinning disks (flywheels) to store energy while they roll downhill. They use that stored energy to lift themselves uphill later on. Their flywheels have relatively small rotational masses but spin at enormous angular speeds. How would a flywheel’s...

### Physics (Rotational Kinetic Energy)

Hello, The question is: A solid ball rolls along the floor with a constant linear speed v. Find the fraction of its total kinetic energy that is in the form of rotational kinetic energy about the center of the ball. Krot/Ktotal = ? The answer I keep getting is 3/1, but the ...

### physics14

A uniform disk with a mass of 900 g and radius 17.0 cm is rotating on frictionless bearings with an rotational speed of 18.0 Hz when Jill drops a 180-g clod of clay on a point 8.70 cm from the center of the disk, where it sticks. What is the new rotational speed of the disk?

### physics

A diver can change his rotational inertia by drawing his arms and legs close to his body in the tuck position. After he leaves the diving board (with some unknown angular velocity), he pulls himself into a ball as closely as possible and makes 2.16 complete rotations in 1.31 s...

### physics

A bicycle has wheels of radius 0.3 m. Each wheel has a rotational inertia of 0.088 kg× m2 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 (...

### Physics

Now your bicycle wheel is rotating with an angular speed of 43.8 rad/s. The wheel has a mass of 4.9 kg and a radius of 48.6 cm. Treat the wheel as a solid thin disc. (a) Calculate the rotational kinetic energy of the wheel in J. (b) Calculate the angular speed the wheel must ...

### ap physics

Suppose that a person closes a car door. The person's fingers are in the door opening, that is located 0.50 m from the hinges. The rotational inertia of the car door is 5.0 kg⋅m2. The door closes in 0.1 s and the rotational speed of the door is 1.4 rad/s just before it ...

### physics

The rate of rotation of most pulsars gradually decreases because rotational kinetic energy is gradually converted into other forms of energy by a variety of complicated friction process. Suppose a pulsar of mass 1.5x10^30 kg and radius 20km is spinning at the rate of 2.1 rev/s...