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.
Homework Statement
Mass m1 = 11.9 kg is on a horizontal surface. Mass m2 = 8.80 kg hangs freely on a rope which is attached to the first mass. The coefficient of static friction between m1 and the horizontal surface is μs = 0.526, while the coefficient of kinetic friction is μk = 0.168...
Hi,
I have a pully with two sticks attached to it as shown in figure. Each stick has a mass in it...which is free to move...and equal iin weight. Assume each mass is equally distant from the pully...what would be the torque on the pully ?..And in which direction the pully move ?
Homework Statement
The pulley is essentially weightless and frictionless. If M1= 10.0 kg and the second mass M2 weighs 98.1 Newtons, what is the tension in the rope and the acceleration of M1 ?
Homework Equations
FT=mg
F=ma
FT = tension
m=mass
g=gravity (9.81)
a=acceleration
The Attempt at a...
Homework Statement
Summary:
The pulley in the figure has radius (R) and a moment of inertia (I). The rope does not slip over the pulley, and the pulley spins on a frictionless axle. The coefficient of kinetic friction between block A and the tabletop is \muk. The system is released from...
Homework Statement
A mass m1 = 5.9 kg rests on a frictionless table. It is connected by a massless and frictionless pulley to a second mass m2 = 2.5 kg that hangs freely.
Homework Equations
1)What is the magnitude of the acceleration of block 1?
2)What is the tension in the string...
I need to adjust the safety trip at 110% of the nominal load ( 130 tons ).
This means that I need to load the overhead crane with 143 Tons. With this load on the floor I start to rise the load with the crane, but I measure less than those 143 Tons ( say 135 Tons). This means that we can never...
While looking for interesting problems, I was led to a problem involving infinite pulleys.
The problem and solution can be found http://www.feynmanlectures.info/solutions/infinite_pulleys_sol_1.pdf" . Now I follow the solution up to the part where he claims \frac{1}{4^{i}M_i} is always...
This question this struck me as fairly simple until I repeatedly tried and failed to get the right answer so any help would be greatly appreciated.
Homework Statement
A block of mass 30 tonnes is to be dragged across the floor by means of the smaller body (mass 5 tonnes) acting through the...
hello,
I have some trouble understanding the force vector of a loaded pulley shaft:
the pulley is driven by the shaft with a torque T, the pulley on his turn is driving a belt.
because of Newton 3th law there's tension in the belt as shown,
ok, now the question: many books state that the...
If mass 1 is 5 kg, and mass 2 is 3 kg, what is the magnitude of tension in the string supporting the pulley, T1?
The answer is 74 N.
What I presume they did was to find tension in the string and then double that to get ~74 Newtons.
My question is: why isn't T1 simply the weight of the...
Homework Statement
An object of mass M=10kg is being pulled up by a system of pulleys.
a)What force do you need to exert on point A for the object to move uniformly ?
b) What force do you need to exert on point A, if the friction in each of the pullies is 0,5N and the pulleys are not massless -...
I am new here so if any other info is needed lmk. :bugeye:
Ok I have been working on this problem for a very long time and there is a possibility that my book's answer is wrong. If that's the case I am going to be very mad ahaha. I put up the diagram and my work is after the passage. I don't...
Homework Statement
Hi. My question is only regarding the early step in this problem that solves for tension. Here is the question:
"In a pulley system where masses m and M are connected by a rope over a massless and frictionless pulley, find the work done by the tension force in lifting mass...
Pulley Question HELP!
Homework Statement
Blocks A and B are connected by a string passing over an essentially frictionless
pulley, When the blocks are in motion, Block A experiences
a force of kinetic friction of magnitude 5.7 N. If mA
5 2.7 kg and mB
5 3.7 kg,
calculate the magnitude...
Homework Statement
problem #62
Homework Equations
Torque = F * radius
Tangential accel = radius * alpha
w = mg
Kinematic equations for linear motion
The Attempt at a Solution
I tried to find the net torque and go from there.
For clockwise torque I got T = 10 * .25 = 2.5 Nm...
If one was to make a pulley to lift something massive like a ship, I am assuming the masses involved of the ship and the counterweight, will mean decreased efficiency due to :
1. Higher friction between in the sheave and axel area.
2. larger cable/robe mass on the longer end (once the pulley...
Homework Statement
(Kleppner & Kolenkow- An Introduction to Mechanics - 2.15)
The image shows the setup. The task is to find the tension in the rope. The coefficient of friction of the sliding blocks with the surface is \mu, and the string is of constant length.
Homework Equations
Newton's...
Homework Statement
Two 0.25 kg blocks are connected by a thread that passes over a frictionless pulley. The thread has no mass, and no friction. The two blocks are in balance. If a third block that weighs 0.20 kg is put on one of the blocks, then what is the acceleration of the 0.20 kg block...
A Particle is attached by a string to a point in a rough inclined plane of elevation \theta. Co-efficient of friction is \mu. Originally, the string is unstretched and lay along the line of greatest slope.Prove that the condition for particle to oscillate is \mu < 1/3tan\theta.
Note : Tension...
Homework Statement
Find the reading of the spring balance shown in the figure (see attachment). The elevator is going up with an acceleration of g/10 , the pulley and the string are light weight and the pulley is smooth.
Homework Equations
F= ma
The Attempt at a Solution
Since...
Homework Statement
Two masses hang across a massless, frictionless pulley. As the masses become infinitely large, the tension becomes:
Homework Equations
F=ma
The Attempt at a Solution
Can someone please help me understand how two masses suspended over a pulley can...
I am using a hydraulic cylinder with a pulley on top. The bottom of the cylinder is fixed and the top has the pulley mounted on it free to rotate. I am trying to double the lifing height of the cylinder. The cylinder stroke is 24inches and I need to make if lift something from the ground up to...
Hi everyone!
I want a string on a pulley to supply the power for the propeller, meaning i pull the string and the force is transformed to the propeller. I was wondering how could i create the system so that i can pull the string time after time and give the propeller more power (keeping...
for a single fixed pulley system :
1. on both sides -equal length ropes
2. equal masses to balance each other (static)
3. ignoring weight of the ropes and friction (pulley, rope, air etc..)
..if no friction- can it be assumed that the next incremental bit of weight on either side- (say a...
Homework Statement
Two blocks of equal mass are connected by a rope of negligible mass that is passed over a frictionless pully. The angle made by the horizontal plane and the ramp is 30 degrees.
a) If neither block moves, what is the required coefficient of static friction to keep the...
Homework Statement
http://img849.imageshack.us/img849/3716/staticeqpulley.jpg
Hopefully the image showed up. If not, here's the link: [PLAIN]http://img707.imageshack.us/img707/3716/staticeqpulley.jpg"
Sorry for the low quality pictures. Hopefully it will do though. The question is: Relate...
Homework Statement
A mass of 11.4kg is connected to a long pinned horizontal rod via a pulley. The rod has a mass of 3.8kg and a length of 1.5m and is connected to a wall with pin A. At the instant where the rod is horizontal, the mass M has a vertical velocity of 6.6m/s.
Assuming the...
Homework Statement
a block of mass m2=4kg hangs by a light string that passes over a massless, frictionless pulley and is connected to a block of mass, m1=6kg that rests on a rough shelf. the coeff of kinetic friction is uk=0.2. the 6 kg block is pushed against a spring, but not attached to...
I need to find the forces in the axial members, loading on the lifting eyes and pulley shaft.
Attached is a photo of the pulley system.
I have no idea where to start so any help would be muchly appreciated.
Homework Statement
http://img41.imageshack.us/img41/589/showmepl.gif
Uploaded with ImageShack.us
Masses m1 and m2 rest on a table 1.2 meters above the floor and are attached to m3 via a very light string and a frictionless pulley as shown above. The coefficient of static friction between...
Homework Statement
[PLAIN]http://img109.imageshack.us/img109/1267/picture2ae.png
m_1 = 2kg
m_2 = 6kg
R = .25cm
M = 10kg
\theta = 30º
\mu = 0.36
Find the acceleration of the system.
Homework Equations
The Attempt at a Solution
m_1 a = T_1 - m_1 g \mu
m_2 a = m_2 g \sin \theta - m_2 g \mu...
Homework Statement
In the system shown below, there is a block of mass M = 4.4 kg resting on a horizontal ledge. The coefficient of kinetic friction between the ledge and the block is 0.25. The block is attached to a string that passes over a pulley, and the other end of the string is...
Homework Statement
Calculate the tension in the cable connecting the two masses. Assume all surfaces are frictionless.
http://tinypic.com/r/20jg36s/7
Homework Equations
The Attempt at a Solution
I tried to begin the solution but came out with a negative acceleration (-2m/s^2)...
Homework Statement
5.Two objects, M = 15.3 kg and m = 8.69 kg are connected with an ideal string and suspended by a pulley (which rotates with no friction) in the shape of a uniform disk with radius R = 7.50 cm and mass Mp = 14.1 kg. The string causes the pulley to rotate without slipping...
Homework Statement
A m2 = 4.63 kg mass is connected by a light cord to a m1 = 2.10 kg mass on a smooth surface (see the figure below).The pulley rotates about a frictionless axle and has a moment of inertia of 0.513 kg•m2 and a radius of 0.257 m. Assuming that the cord does not slip on the...
Homework Statement
how to calculate acceleration and tenstion if i only know mass of bags and mass of weight hanger + slotted weights?
I have mass of 3 bags (A=0.037kg, B=0.08kg, C=0.074kg) and Mass of weight hanger + slotted weights (0.21kg) and need to get T1 and acceleration on bag...
1. Homework Statement
TRIAL 1
A. )
Bag A + 6 stones
Mass (kg) - 0.037 kg
Mass of weight hanger + slotted weights - 210 g/ 0.21kg
Tension 1 (N) - ??
Acceleration (m/s2) - ??
B. )
Bag B + 4 stones
Mass (kg) - 0.08
Mass of weight hanger + slotted weights - 210 g/ 0.21kg
Tension 1 (N) - ...
Homework Statement
Hi, I am having a problem with calculating the proper sizes for a pulley.The pulleys are turning threaded bars and I want them to turn at different speeds. They are connected via a Belt. There are three pulleys arranged in a triangle. One is the driver pulley(Ø31mm) which I...
Hi i need help calculating the shear forces on a pulley shaft. The pulley of the shaft drives another pulley conected to an alternator. the driver pulley is 160mm in diameter, the driven pulley on the alternator is 140mm. The distance between the pulleys is 664mm and the belt length is 1800mm...
Homework Statement
Two inclined planes on either side of a frictionless pulley have angles theta (30 degrees) and phi (60 degrees). On the theta plane is a circular solid cylinder of mass M (1.2 kg) and radius R (.2 m). It is connected by a weightless rope and over the pulley to the other...
Homework Statement
A uniform, solid cylinder with mass M and radius 2R rests on a horizontal tabletop. A string is attached by a yoke to a frictionless axle through the center of the cylinder so that the cylinder can rotate about the axle. The string runs over a disk-shaped pulley with mass M...
i have a simple pulley with a mass a one side and turning handle at the other. i can calculate the tension in the pulley but i am not sure how to calculate the force required to turn the handle and move the mass, or is this simply just equal to the tension in the system?
Pulley, Strings, Friction [Please..]{Mechanics}[not Solved]
Homework Statement
1) I am really confused about how tension is same on both sides of pulley. Also, how do friction of pulley affect tension in string?
2) Also want to know how tension provides torque to pulley since tension in...
Homework Statement
The pulley in the illustration is a uniform disk of mass 2.40 kg and radius 0.220 m. The block applies a constant torque to the pulley, which is free to rotate without friction, resulting in an angular acceleration of magnitude 0.180 rad/s2 for the pulley. As the block falls...
Movers have to haul a piano up to a window that is 5 floors above the ground. They decide to use a pulley system with 6 strands of rope. if the movers can exert a total force of 1111 N, how heavy a piano can they hoist?
It doesn't say where the movers are standing but I'm assuming on the...
Homework Statement
http://imgur.com/MaT4N
Homework Equations
Torque = Fr
The Attempt at a Solution
1) I tried
m2 g r - m1 g r = 1/2 M r^2 * (acceleration / r)
didn't work
2)I tried replace the moment of inertia equation to above equation,still didn't work
Homework Statement
http://apcentral.collegeboard.com/apc/public/repository/ap04_frq_physics_cm_36191.pdf
The problem can be found here. I am stuck on problem 2 d.
Homework Equations
I = m(g-a)R2 / a //found in part c
The Attempt at a Solution
I don't understand why the...
Homework Statement
In Fig. 9.2, two blocks, of masses 2 kg and 3 kg, are connected by a light string that passes over a pulley of moment of inertia 0.004 kgm^2 and radius 5 cm. The coefficient of friction for the table top is 0.30. The blocks are released from rest. Using energy methods, one...
[b]1. A 2.5 kg block and a 1.5 kg block are attached to opposite ends of a light rope. The rope hangs over a solid frictionless pulley that is 30 cm in diameter and has a mass of .75 kg. When the blocks are released, what is the acceleration of the lighter block.
Ok, the book says 2.2m/s^2...
Homework Statement
A block of mass (m1) is attached by a massless string to a pulley of mass (m2) with radius R. Starting from rest, what is the block's speed after it has fallen height h?
Homework Equations
I'll call angular velocity w.
I'm thinking conservation of mechanical energy, so...