Pivot Definition and 131 Threads

Decided to repost for general help with this problem. Homework Statement A particle with charge q and mass m is tied by a (I assumed stiff) string of length L to a pivot point P, all of which lie on a horizontal plane. A uniform electric field E is placed over this system. If the initial...

A straight rod of negligable mass is mounted on a frictionless pivot (see attached diagram)Blocks having masses m_1,m_2 are attched to the rod at distances l_1,l_2. (a) Write an expression for teh gravitational potential energy of the blocks-Earth system as a function of the angle \theta made...

Hi everybody some help needed here! A cube, mass M move with v0 collide with small object "fixed" to the surface in Point P that make it pivot over its side So far I think I understand: During the impact there is no conservation of KE L Angular Momentum : there is an unknown force F...

Homework Statement The thin uniform rod in the figure below has length 2.5 m and can pivot about a horizontal, frictionless pin through one end. It is released from rest at angle θ = 40° above the horizontal. Use the principle of conservation of energy to determine the angular speed of the rod...

Homework Statement A 66 kg sign hung centered from a uniform rod of mass 8.2kg and length 2.3m. At one end the rod is attached to the wall by a pivot; at the other end it's supported by a cable that can withstand a maximum tension of 800 N. what is the minimum height h above the pivot for...

Homework Statement a long, thin rod of mass M and length L is standing stright up on a table. its lower end rotates on a frictionless pivot. a very slight push causes the rod to fall over. as it hits the table, what are (a) the angular velocity and (b) the speed of the tip of the rod...

Help! I've spent 2 days now trying to do this now and it driving me mad. http://www.emvino.com/pivot.jpg Given the following diagram, what distance from the pivot (x) is required to balance the beam? any help would be highly appreciated. Thanks

Homework Statement A uniform rod of mass 1.6 kg is 6 m long. The rod is pivoted about a horizontal, frictionless pin at the end of a thin extension (of negligible mass) a distance of 6 m from the center of mass of the rod. Initially the rod makes an angle of 58 degrees with the horizontal...

Homework Statement A 60-cm-long, 500 g bar rotates in a horizontal plane on an axle that passes through the center of the bar. Compressed air is fed in through the axle, passes through a small hole down the length of the bar, and escapes as air jets from holes at the ends of the bar. The...

Homework Statement http://img151.imageshack.us/img151/6641/torquebk4.jpg Homework Equations T=F*r F*X=Ia I=ML2/3 The Attempt at a Solution I was able to do part A easily enough, but I'm not quite sure where to even start with part B. I know that the force on the pivot point...

Homework Statement A sledgehammer with a mass of 2.60kg is connected to a frictionless pivot at the tip of its handle. The distance from the pivot to the center of mass is rcm=0.610m, and the moment of inertia about the center of mass is Icm=0.04kg*m2. If the hammer is released from rest at...

1. Harry, who weighs 360 N, and 170 N Gretchen are about to play on a 8.00 m long seesaw. He sits at one end and she at the other. Where should the pivot be located if they are to be balanced? 2. F1R1 = F2 R2; F1=360N F2 = 170 N. The problem gives the total length, and I know I need to...

Hey, while reading Kleppner & Kolenkow's discourse on gyrocompasses, I ran into a statement I could not wrap my head around: "The pivots at A and B allow the system to swing freely about the y axis, so there can be no torque along the y-axis." AB is an axis along the y-axis, which is the...

I have a homework question that is referring to a pivot rod with unequal masses. The spheres are small enough that they can be considered point particles. what exactly does this mean? I know how to solve the equation, but I'm assuming I can't use the I=2/5mr^2 to solve it. If the...

Hi All! I am working on the Eddy Currents problem. I was to set up the problem and derive some equations for the pivot pendulum with Eddy currents. Please see attachment. As you see the pendulum swings between max point ( just outside the B field) and enters the B field and then...

"A 50 story building is being planned. It is to be 200 m high with a base of 40 m by 70 m. Its total mass will be about 1.8^7 kg, and its weight therefore 1.8 x 10^8 N. Suppose a 200 km/h wind exerts a force of 950 N/m^2 over the 70 m wide face. Calculate the torque about the potential pivot...

Homework Statement Consider a rod length L and mass m which is pivoted at one end. An object with mass m attached to the free end of the rod. g=9.8 m/s^2. Note: Contrary to the diagram shown, consider the mass at the end of the rod to be a point particle. Basically it looks like a rod...

[SOLVED] Magnitude of the angular acceleration about the pivot point? Homework Statement A uniform horizontal rod of mass 2.7 kg and length 2.4 m is free to pivot about one end as shown. The moment of inertia of the rod about an axis perpendicular to the rod and through the center of mass...

Homework Statement A thin rod of mass 0.630kg and length 1.24m is at rest, hanging vertically from a strong fixed hinge at its top end. Suddenly a horizontal impulsive force (14.7î)N is applied to it. Suppose the force acts at the bottom end of the rod. Find the acceleration of its center of...

Homework Statement There is a sign of mass M that is attached to a rigid bar perpendicular to the ground. There is also a rope attached to the sign at the same point, then pulled out at an angle 45 degrees below the horizontal up to the ceiling. a) Consider the rigid bar to be at...

Homework Statement A force of 10 N is applied to the end of a 0.63 m long torque wrench at an angle 45 degrees from a line joining the pivot point to the handle. What is the magnitude of the torque generated about the pivot point? Homework Equations rFsin= [b]3. The...

Homework Statement The two objects in the figure below are balanced on the pivot, with m = 1.8 kg. What is the distance d? http://i241.photobucket.com/albums/ff4/alg5045/p13-27alt.gif Homework Equations The Attempt at a Solution I haven't attempted a solution because I'm not...

Hi, I just wanted to verify that the Torque that the friction of a pivot would exert against the oscillation of a pendulum was: Torque = \mu m g r Where \mu is the coefficient of friction, m is the total mass that is being supported by the pivot and r is the radius of the axis/rod that...

Homework Statement i need to find the rotational inertia of a rod about a pivot. The rod is of mass M and length L and is attached to a pivot of negligible friction located at a distance of L/3 from the left end of the rod. Homework Equations The Attempt at a Solution i know...

Homework Statement This problem involves a uniform rod of length L with a pivot at point L/4 (so that 1/4 of the rod is behind the pivot and 3/4 is in front of it). The rod is released from a horizontal position and drops down. You need to use conservation of energy to solve for the velocity...

Homework Statement A uniform solid disk of radius (r) 6.71 m and mass (m) 38 kg is free to rotate on a frictionless pivot through a point on its rim. If facing the disk, the pivot is on the left side. The disk is then released. What is the speed of the center of mass when the disk reaches a...

see-saw, force exerted up by pivot? A child weighing 36 N climbs onto the right end of a see-saw, little knowing that it is tired down with a rope at its left end. The see-saw is 2.8 m long, weighs 11 N, and is tilted at an angle of 25 degrees from the horizontal. The center of the mass of the...

Torque? Rotation it has the Word Pivot... A forearm can be modeled as a 2.50 kg, 32-cm-long "beam" that pivots at the elbow and is supported by the biceps. http://session.masteringphysics.com/problemAsset/1001007/10/knight_Figure_13_58.jpg How much force must the biceps exert to hold a 430 g...

I recall my teacher explaining this concept in class, but he did not go over how we would solve these types of problems: Bob the monkey (20 kg) is on a small platform (2 kg), which is attached by massless rods (R = 3m) to a frictionless pivot, and initially at rest...

Hi I got simple question. How is it that determain if a column in matrix is a pivot column? Sincerely Fred

I have a little conceptual question about a rod-pivot system. We have this rod (mass M, length l) pivoting about a fixed point. It is released at 30 degrees above the horizontal, and we're asked for the magnitude and direction force on the pivot when the rod reaches the horizontal. So i...