Pivot Definition and 131 Threads

Pivot Animator (formerly Pivot Stickfigure Animator and usually shortened to Pivot) is a freeware application that allows users to create stick-figure and sprite animations, and save them in the animated GIF format for use on web pages and the AVI format (in Pivot Animator 3 and later).Pivot provides a simple, easy to use interface with a few features. It uses fixed-length 'sticks' to ensure size consistency during animation.

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  1. O

    Rotational motion magnitude question -- Rod mounted on a pivot

    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...
  2. J

    How to Determine Forces on a Right-Angle Slender Bar?

    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...
  3. B

    Projectile hits rod hanging from pivot.

    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...
  4. S

    Calculate Force of Rod at Fixed Pivot Point

    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...
  5. B

    Sliding block transitions to rotation around pivot

    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...
  6. A

    Exploring the Need for a Second Pivot in LU Factorization with Partial Pivoting

    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...
  7. T

    What is the distance from the pivot when the seesaw is balanced?

    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...
  8. V

    Rotation of a non pivot object

    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...
  9. C

    A uniform steel bar swings from a pivot

    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...
  10. C

    Free Pivot Rotation: Calculating Kinetic Energy, Angular Speed & Linear Speed

    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...
  11. I

    How Can I Get This Pivot Point To Stay In One Point?

    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...
  12. L

    Pivot doing work on the rotating rod

    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...
  13. J

    Line of action from pivot to force should be zero?

    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...
  14. C

    Torque without pivot (Torque with only one force)

    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...
  15. K

    Find tension force of a cable and components of reaction force of pivot

    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...
  16. S

    Rod on a pivot: Linear acceleration and reaction forces

    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
  17. V

    Pivot Variables in Reduced Row Echelon Form

    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
  18. N

    What Determines Pivot Positions in a Matrix?

    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...
  19. M

    Finding the Pivot Point of a Chassis: Need Help!

    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?
  20. A

    Pivoted rod - impulse applied so no horizontal force on pivot

    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...
  21. M

    How to Find the Force at the End of a Toggle Clamp Arm?

    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
  22. A

    Pendulum with its pivot accelerating upward

    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...
  23. A

    Will this stick spin if it has no pivot?

    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...
  24. T

    Calculating Force Exerted by a Pivot on a Meter Rule

    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...
  25. E

    Does the Pivot Exert a Moment Reaction for Equilibrium?

    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...
  26. I

    What does it mean to not have a pivot in every row

    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...
  27. S

    Solve Pivot Putty Question - Get Help Now!

    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!
  28. D

    Pivot point of a beam and torque

    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 >...
  29. C

    Lever with offset pivot problem

    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...
  30. T

    Which are the pivot columns? - Linear Algebra

    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...
  31. P

    Finding Pivot Columns in Matrix A & Solving Ax = b

    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...
  32. Y

    What forces are exerted on a pivot and its support in a see-saw lever?

    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...
  33. K

    How to measure a force on a pivot (remedial)

    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...
  34. P

    Finding the Pivot Point for a Seesaw Equilibrium

    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)...
  35. N

    What is a pivot column in a system of linear equations?

    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...
  36. F

    I have a pivot in every row, but it is still not linearly independent

    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...
  37. R

    Text data in excel pivot table

    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...
  38. F

    Are there any pivot columns in this matrix?

    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...
  39. A

    Solve Centripetal Force Equation for Pivot Point

    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...
  40. A

    Friction on a pivot. Graph of motion w/ c.angular accel.

    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...
  41. B

    Angular momentum: bullet through block with rod and pivot

    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...
  42. K

    Lagrangian Equation of motion for rod on pivot in gravitational field

    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...
  43. P

    Finding Tension in a Vertical Circle: A 2.0-kg Ball on a Pivot

    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...
  44. M

    What Position Does the Woman Reach When the Beam Tips?

    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...
  45. U

    Tension force, acting about a pivot

    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...
  46. S

    Calculate Weight on Crane Pivot Points

    Hi there, I've just built a crane (well, actually a jib arm), to be used on a film dolly with a camera on one end and a counterweight on the other to balance it. I'm a bit worried about the weight I'm putting on the bearings and so I started calculating. But I'm having a bit of trouble...
  47. N

    Reaction force on disk by pivot

    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...
  48. P

    Rotational and translational motion of a ruler on a pivot

    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...
  49. J

    How Do You Calculate the Distance for Torque Equilibrium?

    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...
  50. D

    Find the tension in the guy wire and the force on the strut by the pivot.

    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...
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