What is Pulley system: Definition and 352 Discussions
A pulley is a wheel on an axle or shaft that is designed to support movement and change of direction of a taut cable or belt, or transfer of power between the shaft and cable or belt. In the case of a pulley supported by a frame or shell that does not transfer power to a shaft, but is used to guide the cable or exert a force, the supporting shell is called a block, and the pulley may be called a sheave.
A pulley may have a groove or grooves between flanges around its circumference to locate the cable or belt. The drive element of a pulley system can be a rope, cable, belt, or chain.
The earliest evidence of pulleys dates back to Ancient Egypt in the Twelfth Dynasty (1991-1802 BCE) and Mesopotamia in the early 2nd millennium BCE. In Roman Egypt, Hero of Alexandria (c. 10-70 CE) identified the pulley as one of six simple machines used to lift weights. Pulleys are assembled to form a block and tackle in order to provide mechanical advantage to apply large forces. Pulleys are also assembled as part of belt and chain drives in order to transmit power from one rotating shaft to another. Plutarch's Parallel Lives recounts a scene where Archimedes proved the effectiveness of compound pulleys and the block-and-tackle system by using one to pull a fully laden ship towards him as if it was gliding through water.
I am working on making a system of pulleys and a lever. I am planning on using a complex pulley with a few blocks. I wanted to know what how much weight is taken off with the addition of each pulley. If anyone knows some of the equations involved it would be much appreciated. I was planning...
Homework Statement
Frictionless, massless, pulley system. Cables attached to m1 are parallel to the tabletop. Cables attached to m2 are parallel to each other, and perpendicular to the ground. I'm trying to solve for the acceleration of the objects in terms of the variables, m1, m2, g, and...
Homework Statement
2 10 kilogram boxes are connected by a massless string that passes over a massless frictionless pulley. The boxes remain at rest, with the one on the right hanging vertically and the one on the left 2 meters from the bottom of an inclined plane that makes an angle of 60...
1. The drawing shows three objects. They are connected by strings that pass over massless and friction free pulleys. The objects move, and the coefficient of kinetic friction between the middle object and the surface of the table is 0.100
(a) What is the Acceleration of the three objects? (b)...
First, this isn't really a "homework" problem, it is more to help me with my design for an engineering project for ME1000. I'm am trying to model how my "car" will move with my current design. The aim being to power and move a car forward and then launch a projectile using a set weight and...
Homework Statement
See picture: http://session.masteringphysics.com/problemAsset/1038667/6/YF-05-85.jpg
All pulleys are weight- and frictionless, as are the ropes.
Find the acceleration of block m3, of pulley B, of block m1 and m2, the tension in String A, and the tension in string C...
I would like to design an efficient pulley system to pull a fabric which is wrapped around a wooden rod. Is there any pulley system which can reduce the effort to 1/3 rd of the actual?
I have attached some images of the setup.
https://www.physicsforums.com/showthread.php?t=433804"
Hi all! I am working with a problem that for the life of me am having the hardest time with deriving the equation of motion. I have attached the sketch to give a better representation.
The moment of inertia, J, is at the center of the spring. No friction between car and table and cables do...
Homework Statement
The system shown below consists of a block of mass M = 3.6 kg resting on a frictionless horizontal ledge. This block is attached to a string that passes over a pulley, and the other end of the string is attached to a hanging block of mass m = 1.9 kg. The pulley is a...
This is going to seem a somewhat basic question to most people. However, I am trying to build a project where a weight on a pulley weighs 5kg on the way up but 8kg on the way down, then 5kg on the way up and 8kg on the way down, and so on... So its heavier on the way down. I was just wondering...
Homework Statement
Both motors are drawing in the cord at a constant rate of 8 m/s. Determine the speed of the elevator.
Homework Equations
-
The Attempt at a Solution
Using an equation of constraint I got 4Xe - Xb - Xc = constant (Xe being the distance from the roof of the...
Homework Statement
Body B in the figure weighs 102N and Body A weighs 32N, The coefficients of friction between B and the incline are Ms=0.56 and Mk=0.25. Find the acceleration of the system if
a) B is initially at rest
b) B is moving up the incline
c) B is moving down the incline...
I am a bit confused when doing questions about 2 masses connected by a pulley system.
Sometimes i get the right answer when i use just one of the masses to get the acceleration but other times i have to use both masses to get the correct acceleration.
How do you know when to use just one...
Homework Statement
Determine a formula for acceleration of the system shown in Fig. 4-45 if the cord has a non-negligible mass mc. Specify in terms of lA and lB, the length of cord from the respective masses to the pulley ( The total cord length is l= lA + lB)...
Homework Statement
A 5kg mass and a 10kg mass are connected by a rope and hung over a pulley. The pulley is a disc with a mass of 5kg and a radius of 10cm. the two masses are initially at rest with the 10kg mass 50cm higher than the 5kg mass.
Find, The speed of each mass at the instant they...
Detailed modeling of a Pulley System, HELP!
Hello people,
Currently I have a project of a pulley system, and I have to model it with fair detailed equations. Actually this continues from another thread I started sometime ago, but I made a new thread because now I'm continuing with the...
Hello people, this is my first post here in PF and I have a problem with the modeling of a pulley system considering the friction between wire and pulley. I have a similar system as show in the image below and I have a friction factor of 0.25 between wire and pulley, my question is, how can I...
Homework Statement
A car mechanic wants to lift the engine from a car using a rope and pulley
arrangement. He considers two options, shown in Figure Q1a and Figure Q1b. The car engine
has a mass, m, of 200kg, and the maximum force that the mechanic can exert on the rope, P, is
1500N. Use...
Homework Statement
Two objects, m1 = 4.50 kg and m2 = 3.00 kg, are connected by a light string passing over a light frictionless pulley as shown in the figure below. The object of mass 4.50 kg is released from rest, h = 3.00 m above the ground.
(a) Using the isolated system model, determine...
Three blocks are attached by a massless wire. Two blocks are on the incline, and the other is hanging below. The pulley is frictionless; however, the coefficent of friction between the ramp m1 is 0.15. The coefficient of friction between m2 and and the ramp is uknown.
A) Determine the...
The angle is θ = 55.0°. The masses are, for the small pulley, m1 = 3.1 kg, for the traveling pulley, M2 = 5.7 kg, and for the crate, MC = 41.0 kg. What is the minimum tension with which the operator must pull on the cable (assume the cable is of negligible mass) in order to slowly raise the...
Homework Statement
The figure shows two blocks suspended by a cord over a pulley. The mass of black B is twice the mass of black A, m_b = 2m_a = 2m. The mass of the pulley is equal to the mass of black A, m_p = m_a = m, the radius of the pulley is R. The blocks are let free to move and the...
Homework Statement
http://s2.webstarts.com/exploring-my-thought/index.html
Find the kinetic energy of the system of bodies B1, B2 and B3 at an instant when the speed of B1 is 5ft/sec (the image is linked above)
radius of B2 = 2ft
mass of B1 = 32.2lb
mass of B2 = 32.2lb
mass of B3 = 96.6lb...
A 1.5 kg block is attached to a string that is wrapped around the rim of a pulley with a radius of 7.2 cm and a mass of .31 kg. What is the speed of the block after it is dropped .5 m?
Homework Statement
Two masses are places in a frictionless pulley system. Solve for the acceleration and tension force. )its a pullz question and the mu=0.1
Homework Equations
So i know that Fg=MG
Fnet=ma
Ff=MFn
How can i solve this question? how come Fnet=Ft came out of nowhere...
Homework Statement
A 1.0 kg mass and a 4.0 kg mass are attached to a lightweight cord that passes over a frictionless pulley. The hanging masses are free to move. What is the acceleration of the larger mass? What is the tension on the cord?
Homework Equations
F(net...
1. You have a mass hanging off of a frictionless pulley (massless string). The other mass is on a table. The weight of the mass causes the block on the table to slide at an acceleration. There is friction between the block and the table. What would the coefficient of kinetic friction be for this...
Homework Statement
A well pulley is constructed from wooden cylinder with a mass of 5 kg and a radius of 10 cm and a light handle. The bucket filled with water is hanging on the rope coiled to the cylinder has a mass of 7 kg.
- With how much acceleration does the bucket move if the handle...
Block M(15.7kg) is on a horizontal table initially moving to the left because it is connected to a mass m(8.2kg) hanging vertically off of the edge of the table (left hand side of the table). A force F, with a magnitude of 75.3N, acts on M directed at an angle of 35.0 degrees above the...
Homework Statement
The pulley in system drawn below has radius 8.0 cm and mass 0.6 kg. The surface on which the 4.0 kg mass is resting is frictionless. Suppose the 2.0 kg block is released from rest...
Homework Statement
I have dutifully reproduced the problem in OODraw please forgive the poor aesthetic quality but I believe all the important information is visible. Homework Equations
mgL-Lsin(\theta)m'g = \frac{mv^2}{2} + \frac{m'v'^2}{2}
T=T'
v=v'
\therefore v^2 =...
Homework Statement
http://edugen.wiley.com/edugen/courses/crs1650/art/qb/qu/c07/pict_7_42.gif
Figure 7-42 shows a cord attached to a cart that can slide along a frictionless horizontal rail aligned along an x axis. The left end of the cord is pulled over a pulley, of negligible mass and...
I have been trying to find the relationship between the accelerations in a pulley system. My book doesn't explain it.
My first question: Which object moves faster, the one attached to the pulley or the other? I'm guessing the one that isn't attached to the pulley.
My second question: Does...
Homework Statement
Three boxes are connected by cords, one of which wraps over a pulley having negligible friction on it;s axle and negligible mass. The masses are mA=30kg, mB=36kg, and mC= 12kg. When the assemblyis released from rest (a) what is the tension in the cord connecting B and C, and...
my problem is the one shown above. In all honesty i do not know how this system works since a pulley with two radii's has two different cables running through it. Does anyone know where i need to start at with this problem?
Homework Statement
http://img53.imageshack.us/img53/6141/41622697.png Homework Equations
F = ma, all that basic stuff.The Attempt at a Solution
Alright
g = 32.2
Ma = 150/g = 4.66lb
Mb = 75/g = 2.33lb
so Box A
__
|...}==== 2T
|__|
box B
3T
-----|...|______ 60lb
===={__|
Sum of Fx = ma
so...
Homework Statement
My group in physics conducted a lab which is described below:
The lab was to investigate a factor affecting the accel. of an object. We were supposed to change only one factor to see how acceleration would be affected. My group had decided to use a simple static pulley...
Homework Statement
The figure below shows two boxes, m1 and m2. m1 = 10 kg is sitting on a frictionless horizontal surface, while m2 = 7 kg is hanging vertically. The two masses are connected by a massless string that is wrapped around a massless, frictionless pulley.
Figure...
Homework Statement
a mass (m1) on a smooth horizontal surface, connected by a thin cord that passes over a pulley to a second block (m2), which hangs vertically.
If the acceleration is .098 m/s^2 and m1 is 1.0 kg how much must m1 must be to keep it at this acceleration
Homework...
Homework Statement
The Attempt at a Solution
Just want to make sure if my concept is right. If the tension in the string holding m1 is T, the tension on the string holding m2 should be T/2 right?
Thanks.
Hello:
I've attached a drawing of the problem (pretend that the circular things are pulleys, and the strings are straight). A person of mass M stands on a platform of mass m and pulls himself up by 2 ropes which hang over pulleys, as in the attachment. he pulls each rope with force F and...
Homework Statement
Mass m1= (25.70 kg) is on a horizontal surface, connected to mass m2= (5.90 kg) by a light string as shown. The pulley has negligible mass and no friction.
A force of 241.7 N acts on m1 at an angle of 33.30 degrees. The coeficient of kinetic friction between m1 and the...
Homework Statement
We are asked to find the force (F) needed to maintain equilibrium. I've drawn a picture; the red, blue, and green ropes are three separate ropes. Block W has a weight of 500 lbs, pulley A has a weight of 10 lbs, and pulley B has a weight of 20 lbs.
the picture...
Homework Statement
"In the diagram shown below, the lower block is acted on by a force, F, which has a magnitude of 74.4 N. The coefficient of kinetic friction between the lower block and the surface is 0.269. The coefficient of kinetic friction between the lower block and the upper block is...
Homework Statement
"Three blocks are connected on a table as shown in the figure below.
http://i4.photobucket.com/albums/y111/kathy_felldown/sb-pic0550.png
The table is rough and has a coefficient of kinetic friction of 0.360. The three masses are m1 = 3.74 kg, m2 =1.39 kg, and m3 = 1.86...
Homework Statement
a 250 pound mass, is released in rest (hanging at 20 ft) and pulls a 400 pound mass up a ramp with a 30º angle, the coefficient of friction between the 400 pound mass and the ramp is 0.5. Determine the velocity as the 250 pound mass hits the ground
Homework Equations...
This is not a homework problem. It was a problem posed by my professor at the end of the semester but had me puzzled for a while. I was able to satisfactorily solve it for the case when gravity is not present but I was not so successful with gravity.
The question is: to determine the...
Homework Statement
Homework Equations
F=mg=(6kg)(9.81m/s^2)=58.86N
Fx=(cos30)(58.86N)
The Attempt at a Solution
Obviously the triangle somehow interferes with the tension between the top of the pulley and the rope attached to the wall. What really confuses me is how the...
Homework Statement
Three objects m1. m2 and m3 are suspended from three massless and frictionless pulleys as
shown in the diagram. m1 is 6 kg, m2 is 2 kg and m3 is 3 kg. Find the tension of the string
when the system is set in motion (i.e. all masses are moving). Answer in N.
Homework...