What is Rigid bodies: Definition and 127 Discussions
In physics, a rigid body (also known as a rigid object ) is a solid body in which deformation is zero or so small it can be neglected. The distance between any two given points on a rigid body remains constant in time regardless of external forces or moments exerted on it. A rigid body is usually considered as a continuous distribution of mass.
In the study of special relativity, a perfectly rigid body does not exist; and objects can only be assumed to be rigid if they are not moving near the speed of light. In quantum mechanics, a rigid body is usually thought of as a collection of point masses. For instance, molecules (consisting of the point masses: electrons and nuclei) are often seen as rigid bodies (see classification of molecules as rigid rotors).
Edit: Tried to post three times and forum kept adding the prompts. Removed Prompts.
Homework Statement
Three blocks are initially at rest on a level frictionless surface. At t=0s, a three identical forces are applied to a different point on each block.
Each block is a rectangle approximately...
So the situation is like this a ruler (of uniform mass) is pinned to a nail through its center. The has very little friction so it will spin but come to a stop. Initially it is at rest and is sitting perfectly horizontal (so that means the center of mass is at the center of the ruler).
Now I...
Say you have 2 masses connected by a massless string, and another massless string is connected to the rightmost mass. A tension force T acts along this rightmost string, resulting in the string connecting the 2 masses to become taunt.
In these cases, you can treat the 2 masses as one mass...
Problem
Derive Euler's equations of motion for a rigid body from the Lagrange formulation (for generalized coordinate \psi, the third Euler angle).
Applicable Formulae
Euler's equations of motion (what we are trying to derive) are:
I_{1} \dot{\omega_{1}} - \omega_{2} \omega_{3} (I_{2}-I_{3}) =...
Forgive me if this is a noob question. I know there are no perfectly rigid bodies so that if you had a light-year long rod and pushed it, the other end would not move immediately because if it could, then information could be transmitted FTL.
But, what if you pushed on a quark in the same...
Homework Statement
Does it make sense to talk about kinetic energy without specifying, which axis the body is rotation about? I mean, since K = ½ * I * w^2, I have to say that " ... the kinetic energy of the body around the x-axis is ...", right?
Homework Statement
A triangular body changes orientation as the suspporting links rotate. At the moment shown, theta = 90 deg, theta_dot = 5 rad/s, and beta = 45 deg. Determine vA and the angular velocity of the triangular body.
rB/C = 2j cm and rB/A = 5i cm
Points E and D are fixed...
Homework Statement
Point O is fixed in space. Gear 1 has an angular velocity of 20k rad/s, and Gear 2 has an angular velocity of -10k rad/s. r1 = 0.3 m and r2 = 0.2 m. What is the angular velocity of the connecting arm OA, and what is the speed of A?
Gear 1 is larger than Gear 2. Gear 1...
Help me...PLEASEE..
I would like to know about:
1)Background/History:Kinematics of a rigid bodies - linear and angular velocity
2)Application Kinematics of a rigid bodies - linear and angular velocity in dynamics
Please reply me A.S.A.P =(
Homework Statement
Im having real trouble with drawing diagrams for virtual work. Can someone please, please help me!
We were asked, in the diagram i posted, to find 1)vertical reaction at F, 2) all reactions at A, 3) bending moment and shear force at B using virtual work.
i think i...
"Proper" accelerations and rigid bodies.
In Special Relativity, the term "proper" in front of a property means, as I understand it, the value of that property as measured by an observer with test equipment at rest relative to the object being measured. Thus "proper length" is the length...
Hello ,
I've come across a phrase that i don't understand while doing an exercise in this chapter . What's the meaning of a 'uniform paper collar' Please explain to me =) Cheers mate
Well, this is my first post--hopefully I'm posting in the correct forum...
I'm developing a space simulator computer application in which a rigid body's motion is calculated using its linear momentum and rotational momentum. I'm simulating multiple bodies attached together (for example, a...
Hi all! I am having trouble understanding how to create a simulation of a spinning rigid body.
For each axis x, y, and z I have an angle and an angular velocity.
To rotate the object each axis is rotated independently - first the rotation about the x-axis followed by the rotation about...
consider a yo-yo consisting of two cylinders of radius R1, (combined) mass M1, glued to another smaller cylinder of radius R2, mass M2. find the final velocity after falling a height h using Newton's second law. assume the string is vertical.
the inner radius R2 is R0, the outer radius R1 is...
Well here's what I've done. I think I've missed the mark big time with this one...
MI = 2/3 Ma^2
= 2/3 m(2a)^2
= 14/3 ma^2
Initial Energy = 0 + mgh
KE + PE
Energy Just Before Impact = ((1/2 Iw^2)/-KE) + 0/PE
By Energy Conservation
1/2 Iw^2 =...
The motor of a table saw is rotating at 3450 rev/min. A pulley attached to the motor shaft drives a second pulley of half the diameter by means of a V-belt. A circular saw blade of diameter 0.208 m is mounted on the same rotating shaft as the second pulley.
PART A: The operator is careless and...
Question:
"An airplane engine delivers 1.5x10^6 W at an angular velocity of 2400 rev/min."
A) Compute torque developed
B) If a drum of negligible mass, .5m in diameter, were attached to the motor shaft, and the power output of the engine were used to raise a weight hanging from a rope...
Question: "A block of mass m1 = 1.87 kg and a block of mass m2 = 5.84 kg are connected by a massless string over a pulley in the shape of a solid disk having radius R = 0.180m and mass M = 12.7 kg. These blocks are allowed to move on a fixed block-wedge of angle 31.4 degrees as in the figure...
Hi all..new to the forums..
I've got this homework that's been annoying the hell out of me..spent ages trying to do it, but I can't get it.
The problem is attached.
Any help is much appreciated, cheers.
yea...i'm having trouble today with my HW lol
a sign weighing 400 N is suspended at the end of a uniform rod 4.00 m weighing 500 N. what is the tension in the support cable if it makes an angle 40 with the rod?
now I'm curious i don't think Tclockwise = Tcounterclockwise comes into play...
Alright, I'm stuck on this problem.
Two metal disks, Radius 1 = 2.5cm, Mass 1 = 0.8kg and Radius 2 = 5.0cm, Mass 2 = 1.6kg are wielded together and mounted on a frictionless axis through their common center.
The first part asked what is the total moment of inertia of the two discs, which I...
The following comes from Landau's Mechanics, pages 97 - 98.
For a particle in a rigid body, v = V + W x r -- (1)
where for some origin O of the moving body measured in the "fixed" system of
co-ordinates, v = particle's velocity in body in the "fixed" system, V = velocity of O in "fixed"...
I'm having difficulty with the question, perhaps mainly because it is consists completely of unknowns, with little or no numbers. Help, in the form of steps to reach the proof would be much appreciated:
'A uniform ladder of mass M rests in limiting equilibrium with one end on a rough...
This was a question on one of our past exams, and our professor said it was really simple. Of course, he also said that only one person got it of the 400-some people who took the course, possibly because the scenario was very unusual.
Here's what I've done so far:
\overline{I} = 1.686 kg...
Can somebody help me with this problem, it is probably pretty easy but I can not seem to think of how to solve it.
A object initially located at point A on the rim of a grinding wheel rotating about a horizontal axis. The object is dislodged from point A when the diameter through A is...