What is Static equilibrium: Definition and 358 Discussions
In classical mechanics, a particle is in mechanical equilibrium if the net force on that particle is zero. By extension, a physical system made up of many parts is in mechanical equilibrium if the net force on each of its individual parts is zero.In addition to defining mechanical equilibrium in terms of force, there are many alternative definitions for mechanical equilibrium which are all mathematically equivalent. In terms of momentum, a system is in equilibrium if the momentum of its parts is all constant. In terms of velocity, the system is in equilibrium if velocity is constant. In a rotational mechanical equilibrium the angular momentum of the object is conserved and the net torque is zero. More generally in conservative systems, equilibrium is established at a point in configuration space where the gradient of the potential energy with respect to the generalized coordinates is zero.
If a particle in equilibrium has zero velocity, that particle is in static equilibrium. Since all particles in equilibrium have constant velocity, it is always possible to find an inertial reference frame in which the particle is stationary with respect to the frame.
Homework Statement
A 6.3-m long plank is supported by two concrete blocks, one that is placed 2 m from the left end of the plank and another that is placed 1.2 m from the right end. The mass of the plank is 44.5 kg.
(a) Find the normal force from each of the concrete blocks on the plank...
Homework Statement
A 43kg sign hangs by a thin wire slightly off center on a 2.2m long, thin rod. Each end of the rod is supported by a thin wire. the mass of the rod is 18.3kg
1. Determine the tension in each of the 2 wires that support the rod.
2. How far off-center is the wire...
http://session.masteringphysics.com/problemAsset/1007460/26/55544.jpg
What is the equation that results from choosing the pivot point to be the point from which the mass hangs (where W acts)? Express your answer in terms of the unknown quantities T_L and T_R and the known lengths x and L...
I have been working on this problem all day and I cannot figure out how to solve it hopefully somebody has an idea on how to get me moving in the right direction.Homework Statement
Two Identical 15.0-Kg Balls, each 25.0 cm in diameter are suspende by two 35.0-cm wires. The entire Apparatus is...
Homework Statement
Two masses are connected by a string passing over a frictionless pulley. show that for this system to remain in static equilibrium where m1 sin O (theta) > m2 that (static friction coefficient) > or = tan O - m2 / m1 sec O.
Homework Equations
static friction...
Homework Statement
http://img76.imageshack.us/img76/7307/staticsir4.jpg
Homework Equations
i don't know :(
The Attempt at a Solution
I tried but the working is in a notepad, plus I wasnt getting anywhere anyway!
I know its a long questions but this example is essential to my...
Homework Statement
Consider two identical bricks, each of dimensions 20.0 cm x 10.0 cm x 6.0 cm. One is stacked on the other, and the combination is then placed so that they project over the edge of a table. What is the maximum distance that the top brick can extend beyond the table edge...
Homework Statement
A 10-m uniform beam of weight 100 N is supported by two ropes at its ends. If a 400 N person sits at 2.0 m from the left end of the beam, what is the tension in the left rope?
I thought the answer would be:
The Attempt at a Solution
100*5 + 400*7 = T*10
3300 = T*10...
Misako is about to do a push-up. Her center of gravity lies directly above a point on the floor which is d1 = 0.96 m from her feet and d2 = 0.71 m from her hands. If her mass is 50.0 kg, what is the force exerted by the floor on her hands?
F(feet)+F(head)=F(center of gravity0) becuase she is...
[/B]1. Homework Statement [/b]
A cat walks along a uniform plank that is 4.00 m long and has a mass of 7.00 kg. The plank is supported by two sawhorses, one 0.44 m from the left end of the board and the other 1.58 m from its right end. When the cat nears the right end, the plank just begins to...
Homework Statement
A thin metal bar of length L is attached to a pivot point (point A in diagram). The bar is partially submerged in water and it can move freely around an axis that forms a 90 degree angle with the plane of the diagram. The density of the bar is 0.4 g cm^(-3). What...
Homework Statement
A hanging weight with a mass of 25kg is suspended from a rope from a wall. The rope with the weight is wrapped around a pully which is also attached to a different wall. The angle that rope a(rope with mass) makes with the wall is 41 degrees, and the angle of the other rope...
A beam with negligible mass is balanced by two external forces at R1 = 1.5 meters and R2 = 6.5 meters. If F1 = 10 N, what is F2.
i got this:
(10)(1.5) + F2(6.5) = 0
so F2 = 2.31 N
but the second part i don't get:
If the beam actually has a weight of 3 N, what would F2 be now?
In a hydraulic system the piston on the left has a diameter of 4.7 cm and a mass of 1.7 kg. The piston on the right has a diameter of 12 cm and a mass of 3.7 kg. If the density of the fluid is 750 kg/m3, what is the height difference h between the two pistons?
I'm not even sure what equation...
A ladder leans against a frictionlee wall. If the bottom of the ladder is pushed closer to the wall (so theta increases) which of the following change? Why or why not? Assume the ladder is in static equilibrium.
a) Normal force exerted by the ground
b) Normal force exerted by the wall...
A uniform .122kg rod of .90 m length is used to suspend two masses as shown below. At what distance x should the .20kg mass be place to achieve static equilibrium?
Okay so I got the Torque of the 0.2kg mass
T= (0.2)(9.8)(x) with x being the length I hafta find.
Then I got the...
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What force must be exerted by the wind to support a 2.5 kg chicken in the position where one leg is touching the ground 9 cm from the center of mass, the other is up in the air Irrelevant to this problem.
I know...
How far out on a diving board (Fig.12-52 of your text) would a 56-kg diver have to be to exert a torque of 1000 m.N on the board, relative to the left support post?
1000 m*N= (56 kg)(9.8 m/s2)x
1000 m*N=548.8x
x=1.82 m
He would have to walk out 1.82 m on the board.
Is this done...
quick question,
A uniform, aluminum beam 9.00 m long, weighting 300 N, rests symmetrically on two supports 5.00 m apart. A boy weighing 600 N starts at point A and walks toward the right.
How far beyond point B can the boy walk before the beam tips?
ans=1.25 m
How far from the right end of the...
I just want to make sure that I approached the following problem correctly:
A boy carries a sack on one end of a very light stick that is balanced on his shoulder, at an angle of 22.0 degrees up from the horizontal. The mass of the sack is 7.00 kg, and it sits 1.20 m from his shoulder. If his...
Calculate the mass, m, needed in order to suspend the leg shown in Problem 12-5. Assume the leg (with cast) has a mass of 15.0 kg, and its CG is 35.0 cm from the hip joint; the sling is 80.5 cm from the hip joint.
How do I set this up? What equations should be used with this?
You are able to hold out your arm in an outstretched horizontal position because of the action of the deltoid muscle. Assume the humerus bone has a mass m=3.6, length L=0.66 and its center of mass is a distance L1=0.33 from the scapula. (For this problem ignore the rest of the arm.) The deltoid...
A stick with a mass of 0.206 kg and a length of 0.450 m rests in contact with a bowling ball and a rough floor, as shown in the figure below. The bowling ball has a diameter of 21.1 cm, and the angle the stick makes with the horizontal is 30°. You may assume there is no friction between the...
Hi physics fans,
I've made four diagrams for inclusion in a physics lab report. They depict situations in which a meter stick is in static equilibrium (no net torque, no net force). My professor mentioned to me that my analysis of the forces on the stick is not correct, but was not more...
hey every1... I'm stuck on this problem and unless i get it and a few others right I am going to fail my engineering statics course :( I am desperate! I study aerospace engineering but because I've been ill i missed a few classes and i really don't have time to learn the theory to answer...
I need help with the following question.
1. A uniform ladder of mass M and length L leans at an angle A against a frictionless wall. If the coefficient of static friction between the ladder and the ground is Q, what is the minimum angle at which the ladder will not slip?
Answer so far...
If anyone can help me out, i'd really appreciate it. I'm not necessarily looking for the answer, but more how to get to the answer. Thank alot.
A uniform ladder of mass m and length L leans at an angle against a frictionless wall, Fig. 9-61. If the coefficient of static friction between the...
Here's my problem:
An 8.0 m, 200 N ladder rests against a smooth vertical wall. The coefficient of static friction between the ladder and the ground is 0.60, and the ladder makes a 50.0° angle with the ground. How far up the ladder can an 800 N person climb before the ladder begins to slip...
Here is the problem I am attempting to solve:
http://img227.imageshack.us/img227/2747/problempr4.jpg
The large quadriceps muscle in the upper leg terminates at its lower end in a tendon attached to the upper end of the tibia. The forces on the lower leg when the leg is extended are modeled...
There's a question that I'm having trouble with that I do not know exactly how to set up.
Here it is...
A 320g mass and a 400g mass are attached to the two ends of a string that goes over a pulley with a radius of 8.70 cm. Because of friciton, the pulley does not begin to rotate. What...
A 70kg mass is suspended from two cords. One is at 40 degrees with the cieling, and the other is at 30 degrees. What is the tension in both cords?
I got the weight of the object, which is 686N, but how does one know how much of the load each cord supports? I missed this particular physics...
I'm not sure how to go about doing this question. Any help would be great.
A window cleaner of mass 95 kg places a 22-kg ladder against a frictionless
wall, at an angle 65° with the horizontal. The ladder is 10 m long and rests on a
wet floor with a coefficient of static friction equal to...
hi I've been looking at this problem for hours and I am not sure if I am approaching it right.
Q: The boom in the figure [check attachment] is uniform and weighs 2.20kN. The magnitude of the force exerted on the boom by the hinge is...
i knowthe boom has a mass of 224.261 kg, and...
Static Equilibrium?
Summing the moments up from around the center, it is easy to find the intuitive location for the weight at B which would be the same as the A side. But how are there more locations to make this system balance??
A uniform sphere of mass m and radius r is held in place by a massless rope attached to a frictionless wall a distance L above the Centre of the sphere. Find the tension in the rope and the force on the sphere from the wall.
I tried to get a picture, but it is apparently too big to host...
Hello all,
I was wondering if someone could please help with this problem. I have no idea how to do it as no lengths are provided like the practice examples that were used to demonstrate the concept in the readings. Anybody please :rolleyes...
Okay I cannot figure out the answers to any of these question.
1) A uniform steel beam has a mass of 940 kg. On it is resting half of an identical beam. What is the vertical support force at each end? Answers:5.8 x 10^3 N & 8.1 x 10^3N
------- (1/2)beam
--------------- 940 kg beam...
HELP! Static Equilibrium
|_______/
|.../|
|.../ 0 400N
|.../
|/_37?
|
Uniform pole of 6.0 m w/ weight 800N is attached to a vertical wall. A load of 400N hangs from other end of pole. The pole it held by a wire with an angle of 37?.
WHAT is the TENSION of the wire and the HORIZONTAL and...
The problem is stated as follows:
A uniform plank with a length of 6.00 m and mass 31.0 kg rests horizontally across two horizontal bars of a scaffold. The bars are 4.50 m apart, and 1.50 m of the plank hangs over one side of the scaffold.
How far can a painter with a mass of 68.0 kg walk on...
In my Physics 231 class (Calculus Based) I was given a homework problem asking me to prove the following equation. It had a picture attached but the equation was:
Tan (theta) = 1 + (2M / m)
The two (m) represent different masses balanced in equilibrium while hanging with 3 tension forces...
http://www.rwc.uc.edu/koehler/biophys/2h.html
search keyword : " 80 W sin 13 = 40 W l sin 13 + 7 Fj cos 45 "
look at the picture above the keyword you just searched for..
i don't understand why you would add 7 Fj cos45 to the torque equation. I thought we only consider the forces...
A uniform plank of length 6.00m and mass 30.0 kg rests horizontally across two horizontal bars of a scaffold. the bars are 4.50 m apart, and 1.50m of the plank hangs over one side of the scaffold. How far can a painter of mass 70.0kg walk on the overhanging part of the plank before it tips...
God, I took twenty minutes to prepare this, and then it logged me out when I tried to post it, and now I have to retype the whole damn thing. So here goes:
Here is the diagram: http://photobucket.com/albums/v517/shirozu/?action=view¤t=sharkproblem.jpg
Since its almost past ten, and...
Question: A 0.110kg remote control 21.0 cm long rests on a table with a length L overhanging its edge. To operate the power button on this remote requires a force of 0.365 N. How far can the remote control extend beyond the edge of the tabel and still not tip over when you press the power...
How do I do this problem? How do I start?
Problem
I drew all the Forces acting on the body and used Net Torque=0. I still can't find the right answer. So far none of my answers are close. I think my approach is wrong. Can someone give me any hints to help me solve it.
i have found that static equilibrium questions (which require the sum of all forces and torques to be zero) are the most challenging to me.
i don't know why, maybe there are a lot of different type of static equilibrium questions (they always ask the same questions but with different...
6. [PSE6 12.P.022.] Stephen is pushing his sister Joyce in a wheelbarrow when it is stopped by a brick 7.83 cm high (Fig. P12.22). The handles make an angle of 15.0° below the horizontal. A downward force of 389 N is exerted on the wheel, which has a radius of 20.3 cm.
There was a similar...
Was looking for some assistance in setting up the force and torque balance equations for one of those wine bottle holders where the holder is nothing more than a tilted board with a hole in it. I understand that the C.G. of the system needs to be directly above the base of the board but I want...
I've a test soon, and I've been thinking about this, and not quite sure how to approach it. I think I understand the chapter, but I can't seem to get it.
A uniform 210lb telephone pole is sticking out over the Grand Canyon (32 feet of it is sticking out) with a massless cat stuck at the end...