Pivot Definition and 131 Threads

Homework Statement Damped driven oscillator: ruler example. Suppose the ruler used in the classroom demonstration has a length of 12 and 13/16ths inches, a width of 1 ½ inches, is 1/16th inch thick with a density of 1.2 g/cm3. It swings from a pivot point ¼ of an inch from the top end. a) Find...

I've attempted this problem several times and keep getting 14 rads as the answer but its not an available answer choice... any help would be greatly appreciated. The problem: A uniform rod (mass = 2.0 kg, length = 0.6 m) is free to rotate about a frictionless pivot at one end. The rod is...

So this is the question that is given The right-angle uniform slender bar AOB has mass m. If friction at the pivot O is neglected, determine the magnitude of the normal force at A and the magnitude of the pin reaction at O. Now I don't really know where to start whit this or what to do at...

Homework Statement A thin, uniform bar, 2, long and weighing 90N is hanging vertically from the ceiling by a frictionless pivot. It is struck by a small 3kg ball, 1.5m below the ceiling, initially traveling horizontally at 10 m/s. The ball rebounds in the opposite direction with a speed of 6...

Hello, I have not studied any physics or mechanics in a number of years so apologise in advance. Part of my dissertation involves the manufacture of a test rig that will continually strike an implement just above the floor, at a known force. The rig is comprised of a rod with a known...

Homework Statement This isn't strictly homework, but the nature of my problem is similar to homework problems: A block with mass m and it's center of mass not necessarily at the center is sliding along a frictionless surface. The center of mass is distance r from the right front corner of...

Homework Statement Use LU factorization with partial pivoting for the following set of equations: 3x1 - 2x2 + x3 = -10 2x1 + 6x2 - 4x3 = 44 -8x1 - 2x2 + 5x3 = -26The Attempt at a Solution I made an attempt to solve this problem, but my answer was wrong compared to the book. There was an...

Homework Statement It's a balanced seesaw but the pivot isn't in the exact middle and two weights are on it. One at the very end of each side. The weight on the left is 4.8 kg.[m1] The weight on the right is 5.5 kg[m2] The length of the entire seesaw is 5m L1 is the distance from the...

my teacher told.me.that If a rotating uniform stick is falling, the axis of rotation is about the cm of the stick. I don't understand why it is about the cm of the ball. I have searched on google and i found no answer. Can anyone give me some reference so that I can read? Can anyone explain to...

Homework Statement A uniform steel bar swings from a pivot at one end with a period of 1.3 sec. Solve for Length of bar Homework Equations T=2pi*sqrt(L/g)The Attempt at a Solution since the period is 1.3 seconds, I just plug in 1.3 for T and 9.8m/s^2 for g and solve for L i get L= .42m, which...

A thin, cylindrical rod = 26.6 cm long with a mass m = 1.20 kg has a ball of diameter d = 10.00 cm and mass M = 2.00 kg attached to one end. The arrangement is originally vertical and stationary, with the ball at the top as shown in the figure below. The combination is free to pivot about the...

I'm trying to figure out a solution to this design. I want to add a spring to this joint so it can flex up and down and I want the neutral position to be at 45 degrees as pictured. So if you push it either way it springs back to this position. At the same time I dont' want the arm to bounce...

http://dev.physicslab.org/Document.aspx?doctype=3&filename=RotaryMotion_RotationalDynamicsPivotingRods.xmlin this example, the rod is swinging with one end pivoted. conservation of energy was used in this example. the change in potential energy was converted to kinetic energy, and mechanical...

Homework Statement I am seeing the steps on others who have worked this out and they are taking the pin as the pivot position. I thought a force's line of action that passes the pivot position produces zero torque? So i tried to make the center of mass the pivot position and each...

Imagine, I drop a stick with uniform mass horizontally towards the ground. There is only one force acting on it, which is the weight. By common sense, I would know that the stick will not turn. However, mathematically there is a net torque if I set the pivot point on either side of the...

Homework Statement Please see attached photos. I've been drawing and re-drawing diagrams but I'm at a loss. For part a, I've tried a right triangle using the top cable as the hypotenuse. I've tried the force equation (ƩF=ma) but I don't think that's right. I just can't get a start...

Homework Statement Homework Equations r * \alpha = atan r * \omega^2 = arad The Attempt at a Solution arad = (L/2)(3g/L) = 3g/2 atan = (L/2)(3g/2L) = 3g/4

Why do we solve for only the pivot variables when we are trying to solve a system of equations using reduced row echelon form? Thank you

Matrix: Ã= 1 -2 0 0 3 2 -5 -3 -2 6 0 5 15 10 0 2 6 18 8 6 Matrix on reduced echelon form: 1 0 0 -2 3 0 1 0 -1 0 0 0 1 1 0 0 0 0 0 0 X 0 0 -2 3 0 X 0 -1 0 0 0 X 1 0 0 0 0 0 0 Are the pivot positions the ones I've marked with X? And therefor colum 1, 2 and 3 are pivot columns...

I am having some real trouble with this, could anybody help, attached is a picture of a chassis with some weights on etc, i need to find out where the pivot point would be. i can't move any of the objects around, does anybody know how to do it?

Homework Statement There is a rod of length L pivoted on one end. It is originally at rest horizontally then released. When vertical, an impulse is applied to bring the rod to rest. Throughout the question I have worked out I = 1/3 mL^2 w= √(3g/L) at the vertical position and an...

i want to use a swivel type pneumatic cylinder to make a toggle clamp with a swinging arm along a pivot. the line diagram is shown in the figure can anyone help me finding the force at the end of arm. force by cylinder on one end of arm= 300kg

A pendulum of length, b, and bob with mass, m, is attached to a massless support moving vertically upward with constant acceleration a. Find the equation of motion. This problem is easy with the help of Lagrangian dynamics: bθ''+(g+a)θ=0 But how to solve this problem using Newton's...

Hi all, Here is what I am trying to understand qualitatively. It is NOT a homework problem: A long, one-dimensional rod of mass M and length L is in free space. There is no gravity, no forces, and no pivot. Its just a rod sitting there, floating, with nothing else around. Let's say its L=0...

Homework Statement The weight of a uniform meter rule is 1.5N. Calculate the force exerted by the pivot on the meter rule. The answer in the back of the book say it is magnitude of 0.5N downwards, I have tried every combo of equation from m=f*d to W=m*g There are 3 question before...

I know that the pivot exerts a vertical reaction equal to Cy = w0L / 2 and a horizontal reaction equal to Cx = 0. Does the pivot also exert a moment reaction? My intuition says that it doesn't and that it's actually not in equilibrium because it will rotate about the pivot, but the question is...

I am trying to fully understand this theorem Theorem: Let A be an m x n matrix. The following are all true or all false. 1. For each b in Rm, the equation Ax has a solution 2. Each b in Rm is a linear combination of the columns of A. 3. The columns of A span Rm 4. A has a pivot position...

Can someone please help me solve this: http://wug.physics.uiuc.edu/cgi/courses/shell/per/phys111/ie.pl?11/IE_putty_plus_rod pivot putty question? Any help would be greatly appreciated!

Homework Statement A beam is supported only at one point, called the pivot point, as shown in the diagram. A block with mass m1 sits at the left end of the beam, a distance L1 from the pivot point. A block with mass m2 sits at the right end of the beam, a distance L2 from the pivot point. L2 >...

Homework Statement I have a situation a shown in the diagram below. A lever with a gas compression spring opposing it's turning. I want to find the force acting on the spring, F1, for a given inital force @ F0. [PLAIN]http://img18.imageshack.us/img18/9830/lever01.png Homework...

Homework Statement Given matrix A= 1 1 -2 1 3 2 -1 2 2 6 3 2 -4 -3 -9 x= x1 x2 x3 x4 x5 b = 1 2 3 1. Solve the system by elimination (use the augmented matrix) until pivots are found (no backward elimination here). 2. Show that pivots...

Homework Statement So, I want to find the pivot columns to the matrix A: A= -1 1 -5 0 2 3 0 6 1 -1 2 -1 7 2 1 2 -7 25 5 1 and after that I want to solve Ax = b where b is (I kind of want to solve Ax = 0 as well, but let's skip that...): b= a+3 2a -a-1 -9a-5 My thought was...

Hi there, I have a two part question, just for my understanding not homework. Say you had a see-saw type lever like in my attachment. The yellow ball represents a 1N force and the green 2N and they are both 1m from the pivot. The blue bar is a beam attached hanging down directly off the lever...

Hi all, I apologize now at how elementary this is, but I have been all over google and I cannot get a straight answer. My question seems to me be to be quite easy. Maybe I am over simplifying it. Anyways, any help is much appreciated. Btw, it's been 15 years since my last physics class...

Homework Statement A 442.3 N person and a 286.1 N person sit on either end of a 2.65 m long seesaw. Where along the seesaw should the pivot point be placed to ensure rotational equilibrium? Homework Equations F=ma The Attempt at a Solution 442.3x=286.1(2.65-x)...

Homework Statement What is a pivot column?Homework Equations The Attempt at a Solution I tried google for some examples but I cannot find any. I need to know what exactly a pivot column is because I am trying to do a Linear Algebra problem about consistency and inconsistency. Can anyone...

Homework Statement I need to argue this properly Let's say I have a matrix A and rref(A) is given as \begin{bmatrix} 1 & 0&-1 \\ 0& 1 & -1 \end{bmatrix} Since I have a pivot in every row, why isn't this linearly independent? Don't give me other arguments like "because there...

Using Excel 2003, I'd like to display text data in the Data Items area of a pivot table. Currently, I see the number 1 in the field. I've changed the format to "Text", which has no effect on the data that's displayed. Is it possible to display text data in the Data Item area of a pivot table...

Homework Statement Just need help identifying pivots columns \begin{bmatrix} 1 & 1 & 1 &1 &1\\ 0& 0& 0& 0&0\\ 0& 0& 0& 0&9 \end{bmatrix} From my understanding, any column with 1s and everything below it 0s are all pivot columns right? Is the above all pivot columns...

as you all know the equation for centripetal force is (m((2 pie r)/t)^2)/r). ok so imagine this. a weight attached to a string attached to a pivot point. the weight is rotating around the pivot point. the pivot point can move back and forth along the x axis. if looking at a x, y graph. the pivot...

Quick question, if an applied friction is applied on a pivot, will a rotating object slow down? or nothing will happen? Friction usually slows down objects in linear motions, but I don't know what it does on rotating objects. What does a graph of a angular speed look like with constant...

7. 0/10 points All Submissions Notes Question: SerPSE8 11.P.037. Question part Points Submissions 1 2 0/5 0/5 4/100 2/100 Total 0/10 A wooden block of mass M resting on a frictionless, horizontal surface is attached to a rigid rod of length script i and of negligible mass. The rod...

Homework Statement I am trying to get an equation of motion for the following (seemingly simple) setup. You place on a rod on a pivot. The rod's centre of mass is precisely over the pivot. Think of balancing a ruler horizontally on your finger. Gravity, of course acts downward. The...

Homework Statement A 2.0-kg ball is attached to a light rod that is 1.2 m long. The other end of the rod is loosely pinned at a frictionless pivot. The rod is raised until it is inverted, with the ball above the pivot. The rod is released and the ball moves in a vertical circle. The tension in...

Homework Statement A beam resting on two pivots has a length of L = 6.00 m and mass M = 72.0 kg. The pivot under the left end exerts a normal force n1 on the beam, and the second pivot placed a distance l = 4.00 m from the left end exerts a normal force n2. A woman of mass m = 51.1 kg steps...

Homework Statement A mass of 20kg is hanging on a rope. Another cord is tied to the rope part way down and is attached to a wall. This causes the rope to make a 60 degree angle to the ceiling. a) Calculate the tension force in the upper section of the rope. b) Calculate the force exerted by...

Homework Statement A uniform disk of mass M and radius R is pivoted about a point on its edge. The disk is released from rest when its center of mass is at the same height as the pivot. What is the reaction force exerted on the disk by the pivot the initial instant the disk is released? The...

Homework Statement A ruler is attached to the top of a pole bound by its center (pivot point of the ruler is at its center). A student briefly exerts a downward force on the right end of the ruler. The magnitude of the force exerted by the student is less than the weight of the ruler. Assume...

Homework Statement The two objects in the figure below are balanced on the pivot, with m = 2.4 kg. What is the distance d? http://www.webassign.net/knight/p13-27alt.gif Homework Equations T=rf The Attempt at a Solution 2.4kg + 4.0 kg= 6.4kg 6.4kg/2= 3.2kg on each side of...

1. Find the tension in the guy wire and the force on the strut by the pivot. http://img16.imageshack.us/img16/382/tension.png Homework Equations I think Fwsin30 and Fwsin40 is applicable here to find tension.The Attempt at a Solution The information provided is EXTREMELY vague in my opinion...