What is Rotational motion: Definition and 610 Discussions
A rotation is a circular movement of an object around a center (or point) of rotation. The geometric plane along which the rotation occurs is called the rotation plane, and the imaginary line extending from the center and perpendicular to the rotation plane is called the rotation axis ( AK-seez). A three-dimensional object can always be rotated about an infinite number of rotation axes.
If the rotation axis passes internally through the body's own center of mass, then the body is said to be autorotating or spinning, and the surface intersection of the axis can be called a pole. A rotation around a completely external axis, e.g. the planet Earth around the Sun, is called revolving or orbiting, typically when it is produced by gravity, and the ends of the rotation axis can be called the orbital poles.
Homework Statement
Two identical soccer balls are released from rest from the top of ramp consisting of a straight section connected to a circular section having the shape shown at right (height of ramp from where ball is released to bottom of curve is 4.0m. The radius of the curve is 1.5m)...
Homework Statement
Two identical soccer balls are released from rest from the top of ramp consisting of a straight section connected to a circular section having the shape shown at right (height of ramp from where ball is released to bottom of curve is 4.0m. The radius of the curve is 1.5m)...
Homework Statement
The flywheel of a steam engine begins to rotate from rest with a constant angular acceleration of 1.35 rad/s^2. It accelerates for 33.1 s, then maintains a constant angular velocity. Calculate the total angle through which the wheel has turned 47.5 s after it begins...
Homework Statement
A bicycle has wheels with a diameter of .600 m. It accelerates uniformly and the rate of rotation of its wheels increases from 215rpm to 275rpm in a time of 24.3 seconds. Find the linear acceleration of bicycle.
Homework Equations
w =wi + alpha(time)
The Attempt...
A thin, uniform stick of length 2.1 m and mass 4.2 kg is pinned through one end and is free to rotate. The stick is initially hanging vertically and at rest. You then rotate the stick so that you are holding it horizontally. You release the stick from that horizontal position. Remember that the...
1. Homework Statement
Two masses, m1 and m2, are connected by light cables to the perimeters of two cylinders of radii, r1 and r2, respectively. The cylinders are rigidly connected to each other but are free to rotate without friction on a common axle. The moment of inertia of the pair of...
Homework Statement
A solid sphere with mass "m" and radius "r", slides (without rotating) on a frictionless horizontal surface, with speed of V[0].
At time t[0] the sphere roll on a surface with friction "u", at time t[0] the ball is starts rotating as it glides aswell. At time t[1] the...
Hello everybody. I have a rather strange question regarding the rotational motion of a solid object across an incline plane. I wonder if it is possible for a solid object to move upwards the plane without the application of any external force, other than its own weight and the friction with the...
I've attached the problem as a .jpg file. The mass obviously has potential energy. Is this simply converted to the kinetic energy of the mass plus the two kinetic energies of the pulleys? I also don't see how I would find the angular speed (probably don't even need to) of the pulleys. Cant...
I've also attached the picture of this problem at the end of the post.
A uniform rod of mass 4:5 kg is 10mlong. The
rod is pivoted about a horizontal, frictionless
pin at the end of a thin extension (of negligible
mass) a distance 10 m from the center of
mass of the rod. Initially the rod...
I've been having difficulties solving this problem. I will say how I have been trying to solve it beneath the question.
A .005 kg nickel rests .100 m from the center of a record player at rest. The nickel and player have a coefficient of friction of .33.
a) If the player can accelerate at...
Every rotational motion have torque? Pls come and take a look..
Are torque exsiting at every rotational motion?
how about free fall or wheel rotating without any force act on it??
Question:
A 0.8m diameter, 50kg flywheel with a radius of gyration of 0.283m must be braked from 60 rpm to...
1. I need some ideas on how to demonstrate angular velocity and angular acceleration in the class.
3. We have some wheels w/ handles on either side that we can use to show rotation. We're going to apply the equations of angular velocity and acceleration to that. Does anyone have any...
Homework Statement
A digital audio compact disc carries data, with each bit occupying 0.6 (mu)m, along a continuous spiral track from the inner circumference of the disc to the outside edge. A CD player turns the disc to carry the track counterclockwise above a lens at a constant speed of 1.3...
One end of a meter stick is pinned to a table, so the stick can rotate freely in a plane parallel to the tabletop. Two forces, both parallel to the tabletop, are applied to the stick in such a way that the net torque is zero. One force has a magnitude of 1.90 N and is applied perpendicular to...
Homework Statement
A wheel decellerates from 100 rpm in 10 sec. Find angular acceleration, torque and the force torque is producing on a fixed object.
The wheel has a radius of .0025m and a mass of 50kg.
Homework Equations
T=Ia
a=ra
T=dL/dt
The Attempt at a Solution
The first...
Homework Statement
A stuntman whose mass is 70 kg swings from the end of a 4.0-m-long rope along the arc of a vertical circle. Assuming he starts from rest when the rope is horizontal, find the tensions on the rope that are required to make him follow his circular path,(a) at the beginning of...
Hey everyone, first time poster here:smile: It's a really great forum though!
I can't seem to figure out this problem. If anyone could help that would be great.
1.A bicycle has wheels with a diameter of 0.650 m. It accelerates uniformly and the rate of rotation of its wheels increases...
1. A uniform stick of mass m and length l spins arounds on a frictionless horizontal table, with its CM stationary (but not fixed by a pivot). A mass M is placed on the plane, and the end of the stick collides elastically with it, as shown. What should M be so that after the collision the...
Hi. I did a 5 part problem and I just want to know if I did it right or if I'm on the right track. Please help. Thank you. The problem is as follows:
Two identical grinding wheels of mass m and radius r are initially spinning about their centers. Wheel A has an intial angular speed of w...
A cylinder is observed to be rolling freely at a constant speed on a horizontal surface. Which of the following statements is true?
a.It is possible that the cylinder is both rolling and sliding at the same time, i.e. that v, the speed of the centerpoint, is not = to rw.
b.If the cylinder...
Ok the problem is:
Energy is to be stored in a flywheel in the shape of a uniform solid disk with a radius of 1.30 m and a mass of 72.0 kg. To prevent structural failure of the flywheel, the maximum allowed radial acceleration of a point on its rim is 3600 m/s^2.
What I did was solve for...
It looks like your standard matchbox car loop.
I need to find the minimum height h that will allow a solid cylinder of mass m and radius r_1 to loop the loop of radius r_2. "Express h in terms of the radius r_2 of the loop."
I am not quite getting a certain portion of this. I know the...
"Consider the bicycle wheel is not turning initially. A block of mass m is attached (with a massless string) to a wheel. The block is allowed to fall a distance of h. Assume that the wheel has a moment of inertia I about its rotation axis.
Find the angular speed of the wheel after the block...
These problems have diagrams with them so I posted those pictures are at
http://viewmorepics.myspace.com/index.cfm?fuseaction=viewImage&friendID=21023924&imageID=1420239256
1) A spherical ball rolls up an incline. Determine the acceleration of the ball and the magnitude and direction of...
Hi, I'm really confused about these 2 problems to the extent that I have no idea where to start.
Any kind of suggestions and hints would be really appreciated.
Thanks
A 1090-N uniform beam is attached to a vertical wall at one end and is supported by a cable at the other end. A...
One more problem on a tough worksheet...I have tried it for a while, but can't find an equation(s) suitable for the problem...
A constant force of 12N is applied to the axle of a disc rolling along a flat plane. The disc has mass m=22kg, diameter D=.50m, and rotational inertia I=.688kgm^2...
This question really has me stumped. Am I right to just ignore the fact that there is an inner control room ring?
This is what I think I will need:
We haven't gotten to inertia yet, but I think this is an inertia problem.
I = MR^2 (if I take out the inner ring and say it is a thin-walled...
I'm having trouble with these two "classic meter stick problems"
1: A rod of length L and mass M stands vertically on a flat frictionless surface. A wad of putty of mass m and initial velocity v strikes the stick at a right angle at height 3/4 L. The collision is perfectly inelastic. Find the...
Why is it that when you spin a piece of plastic bent slightly upwards on a flat surface, it spins normally for a little while, slows down, and then spins the other way for a bit before stopping? My professor did a demo of this in class and didn't really explain it.
The Sun subtends an angle of about 0.5 degrees to us on the Earth, 150 million km away. What is the radius of the Sun?
theta=l/R
(2pi rad/360 degrees)0.5 degrees=2pi(150,000,000 km)
This should be simple, but the answer I get seems to not sound right at all
Have i set this up correctly?
Rotational Motion on an Axis Problem: Helpppp?
Problem: Two thin rectangular sheets (0.20 m x 0.40 m) are identical. In the first sheet the axis of rotation lies along the 0.20-m side, and in the second it lies along the 0.40-m side. The same torque is applied to each sheet. The first sheet...
Ok, here's a problem on a quiz that i just can't figure out. I'm having trouble drawing it in the first place:
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At the moment before a diver jumps from a diving board, a force of 1.200 X 10^3 N is exerted on teh diver at an angle of 90 degrees to the board. This force produces a...
A 32.0 kg wheel, essentially a thin hoop with radius 1.20 m is rotating at 280 rev/min. It must be brought to a stop in 15.0s (a) How much work must be done to stop it?
t=15.0s
m=32.0kg
r=1.20m
ω= 29.3 rad/s after conversion
I need to find W
I think I need to find torque in order to find...
hey guys, jus wunna see how u solve this question.
-a car traveling on a flat(unbanked) circular track accelerates uniformly from rest with a tangetial acceleration of 1.70m/s(squared). the car makes it one fourth of the way around the circle before it skids off the track. cetermine the...
Hey guys i have only one question this time on my homework :cool:
1) At t=0 a grinding wheel has an angular velocity of 28.0 rad/s. It has a constant angular acceleration of 29.0 rad/s^2 until a circuit breaker trips at time t=2.50s. From then on, it turns through an angle 433rad as it...
Hey everyone,
Okay, so I'm just not sure how to solve this problem exactly and could use some kind advice.
A heavy ball is connected on the end of a light rope and undergoing rotation witha radius of X, let's say. At t= 19.3s a=10.2m/s^2. At t=7.4s what was the acceleration.
How does...
The tires of a car make 85 revolutions as the car reduces its speed uniformly from 90 km/h to 30 km/h. The tires have a diameter of 0.80 m.
(a) What was the angular acceleration of the tires?
rad/s2
angular acceleration = Omega final- Omega intial / Delta Time
does that mean that in...
the question is about that:
Ayo-yo is made from two uniform disks, each with mass m and radius R,
connected by a light axle of radius b. A light, thin string is wound several times around the axle and then held stationary while the yo-yo is released from rest, dropping as the string unwinds...
I figured out the first part of the problem below, but I haven't been able to solve the second part.
http://img148.imageshack.us/img148/2097/untitled13jb.png
http://img89.imageshack.us/img89/5061/untitled6ez.png
What I have so far:
I solved for angular acceleration with alpha = v...
Thanks in advance for the help. Here are the problems:
A uniform rod is free to rotate about a frictionless pivot at one end. The rod is released from rest in the horizontal position. What is the magnitude of the angular acceleration of the rod at the instant it is 60 degrees below the...
A uniform 2.9-kg cylinder can rotate about an axis through its center at O. The forces applied are: F1 = 2.4 N, F2 = 3.9 N, F3 = 6.1 N, and F4 = 4.6 N. Also, R1 = 11.2 cm and R3 = 4.0 cm. Find the magnitude and direction (+: counterclockwise; -: clockwise) of the angular acceleration of the...
A small spherical ball of radius r = 1.5 cm rolls without slipping down a ramp and around a loop-the-loop of radius R = 2.6 m. The ball has mass M = 358 g.
How high above the top of the loop must it be released in order that the ball just makes it around the loop?
---
i just calculated the...
This is the doubt that troubled me when the chapter of rotational motion started. If torque is applied on a body for sometime and then the torque is stopped, then will the body continue to rotate for ever?
Yes - coz the rotational Kinetic energy Iw^2 must be conserved since no mommentum is...
A disk with a radial line painted on it is mounted on an axle perpendicular to it and running through its center. It is initially at rest, with the line at q0 = -90°. The disk then undergoes constant angular acceleration. After accelerating for 3.1 s, the reference line has been moved part way...
Some times it becomes very difficult to differenciate between Circular motion and Rotational motion.Can anyone tell me to understand clearcut diff. between the two?
The drawing shows the top view of two doors. The doors are uniform and identical. Door A rotates about an axis through its left edge, and door B rotates about an axis through the center. The same force is applied perpendicular to each door at its right edge, and the force remains perpendicular...
Hint: Consider the wheel's energy.
Consider a wheel of radius 1.23 m, mass
7.7 kg and moment of inertia I =1/2 MR^2
(it's a solid disk). The wheel rolls without
slipping in a straight line in an uphill direction 30 degrees above the horizontal. The wheel starts at angular speed 16.1 rad/s...