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.
Pulley Tension friction help??
Homework Statement
http://www.flickr.com/photos/72384417@N06/6533043261/ by LiFK1, on Flickr
Mass1 = 0.750 kg
Mass2 = 0.52 kg
Fk=2.1 N
g= 9.8 N
Homework Equations
F=ma
Mass1(gravity)= (Mass1+mass2)Acceleration
T + m2g - fk = (m1 + m2)a...
Homework Statement
In the figure below, M1=1.00 kg, M2=2.00 kg and M3=4.00 kg. Theta is 30.0°. The pulley and all surfaces are frictionless. Find the tension in the two strings and the direction (entire system to the left/counterclockwise or entire system to the right/clockwise) and...
An green hoop with mass mh = 2.4 kg and radius Rh = 0.18 m hangs from a string that goes over a blue solid disk pulley with mass md = 2.4 kg and radius Rd = 0.09 m. The other end of the string is attached to a massless axel through the center of an orange sphere on a flat horizontal surface that...
Homework Statement
A pulley with mass Mp and a radius Rp is attached to the ceiling, in a gravity field of 9.81 m/s2 and rotates with no friction about its pivot. Mass M2 is larger than mass m1. The quantities Tn and g are magnitudes.
(image attached)
Select T-True, F-False, G-Greater than...
Homework Statement
A 26.3 kg block (m1) is on a horizontal surface, connected to a 7.10 kg block (m2) by a massless string as shown in the figure below. The frictionless pulley has a radius R = 0.060 m and a moment of inertia I=0.090 kgm2. A force F = 220.1 N acts on m1 at an angle theta =...
Homework Statement
Two 20 kg masses rest on a horizontal table. The bottom mass is connected to a string of negligible mass, which passes over a frictionless pulley with negligible mass and supports a third 20 kg mass that hangs over the side of the table. The coefficient of kinetic friction...
Question: Mass one is 15.0 kg and mass 2 is 9.0 kg. They are connected by a massless rope which passes over a frictionless pulley. The pulley has a shape of a solid disk. They pulley mass is 8.0 kg and the pulley radius (R) is 0.20 meter.
What is the speed of the falling body?
Solution:
I...
Homework Statement
Mass of box: 27.0 kg
mass of bucket attached to pulley: 25.0 kg
incline:35 degrees
static friction:.650
kinetic friciton: .490
Okay, there is a box on an incline. The box is attached to a pulley. A bucket is attached to the other end of the pulley. The bucket is going...
Hi guys,
I am working on a simple belt and pulley question, as pictured below.
To find the magnitude, I used the following equation:
(g(M-m))/(M+m)
So,
9.81(2500-600)/(2500+600) = 6.01 - Answer = 6kN
Is this correct, or am I doing it totally wrong? I have searched for the...
Homework Statement
Use Newton's 2nd Law, sum of torques, and kinematic equations to determine the angular speed of the spool shown in the figure below. Assume the string has a negligible mass, and it turns without slipping. Use g=10 m/s2 for acceleration due to gravity.
Homework...
Homework Statement
A pulley containing only a single mass, m, is hanging vertically from a mass with spring constant k. Find the period of vertical oscillation for the mass. Explanation in terms of energy and energy conservation is preferred.Homework Equations
Ay, there's the rub. You are...
Homework Statement
20 Kg box is raised 0.75m by a constant 25N force applied at the end of the cord if the pulleys are massless, determine work done on the crate. What is the power delivered at the end of the cord at this point?
Identical pulley system...
Homework Statement
A string is attached on a pulley, with Mass 1 (2 kg) hanging from the left and Mass 2 (5 kg) hanging from the right. The pulley itself is being pulled upwards with a force of 100N.
Find the tension T in the string, and the accelerations of both masses.
We consider...
Homework Statement
In the diagram, the pulley is frictionless and the ropes are massless. You are given that m1 = 10.0 kg and m2 = 29.5 kg.
Calculate the acceleration of m2 downwards.
What is the magnitude of the tension in the string? Homework Equations
sum of F= M*A
The Attempt at a...
Homework Statement
i'm having a lot of trouble with this question.
A pulley, consisting of a 0.40 m diameter wheel mounted on a horizontal frictionless axle, is firmly attached to the ceiling. A light rope wrapped around the pulley supports a 0.50 kg object, as shown in the diagram...
heres the problem and its solution:
I understand how to find reactions etc etc, the only thing that i don't understand is how to calculate the net forces that are acting on the pulley. the tension in the line is trying to "straighten" the line out, the pulley is fighting this force to...
Homework Statement
Two forces are applied to a pulley with a moment of inertia I = .15kg*m^2.
The pulley is mounted so that its frictionless axle is fixed in place.
1) What is the angular acceleration of the pulley?
2) If the pulley starts from rest, how long does it take to undergo...
Homework Statement
Consider two masses of 3.3 kg and 7.4 kg
connected by a string passing over a pulley
having a moment of inertia 12 g · m2
about its axis of rotation, as in the figure below. The
string does not slip on the pulley, and the
system is released from rest. The radius of
the...
A massless spring of constant k=196 N/m is used to suspend the mass M=1.45 kg (including the pulley), as shown in the attached figure. What is the frequency of simple harmonic motion?
Relevant equations
f = 1/period
T = 2pi*sqrt(M/k)
Tension = 1/2Mg
What I tried...
T(tension on...
Homework Statement
An green hoop with mass mh = 2.4 kg and radius Rh = 0.12 m hangs from a string that goes over a blue solid disk pulley with mass md = 2.4 kg and radius Rd = 0.11 m. The other end of the string is attached to a massless axel through the center of an orange sphere on a...
Homework Statement
A crate is pulled up using frictionless pulleys in the manner shown in the figure. The angle is 45 degrees. The masses are, for the small pulley, m1=4.1 kg, for the traveling pulley, M2=6.7 kg, and for the crate, MC=45.8 kg. What is the minimum tension with which the...
Homework Statement
An 8kg block rests on an inclined plane where theta=37 degrees. The coefficient of kinetic friction on the plane is .23. The 8kg block is connect by a massless, frictionless pully to a hanging 16kg block. The blocks are released from rest. What is the acceleration...
Homework Statement
A man having a weight of 150 lb supports himself by means of the cable and
pulley shown in the figure. If the seat has a weight of 15 lb, determine the force that must
be exerted on cable at A, and the normal force the man exerts on the seat.
Answers provided by the...
Homework Statement
Two boxes are attached to opposite ends of a rope passing over a frictionless pulley as shown below. The mass of Box A is 15kg and the mass of box B is 12kg. The system is originally at rest with the bottom of box A at a height of o.85m above the floor. When the system is...
I think I'm over thinking this, so someone set me straight.
If I have an eletric motor with a 75mm OD shaft making 1450Nm of torque, and
I add a 7in pulley/sheave to the motor shaft.
Would the torque change? Half of me says yes other half of my brain thinks no.
Torque = Force *...
Homework Statement
The three blocks are attached via a massless, frictionless pulley system, as
shown. The frictionless plane is inclined at an angle = 60 degrees. When released
from rest, the 20kg block will start to slide down the plane. Find the tension in the
string.
The image is...
Homework Statement
The masses of blocks A,B, and C are 4kg, 10kg and 2kg respectively. Knowing that P=0 and neglecting the masses of the pulleys and the effects of friction, determine a) the acceleration of each block and the tension in the chord.
Homework Equations
Fnet=ma
The...
Homework Statement
I'm currently doing a lab that focuses on a pulley and have got stuck on on part.
The goal here is to use the data from the Atwood’s pulley experiment to test the validity of (m1-m2)g=(m1+m2+1/R^2)a. In this equation, take the quantity (m1−m2)g as the y variable and the...
A mass M in held in place by the applied force F and the pulley system shown below. The pulleys are massless and frictionless. Determine the tension in each section in each section of rope and the applied force F
Taking upwards as positve
-T1 - F = 0
T4 - T1 - T3 = 0
T2 + T3 - T5 = 0...
Ok so I'm in college upgrading, and doing my physics 20. I have a hand in assignment due Wednesday and I can't for the life of me figure out these two questions.
6. The 4.0kg block shown accelerates across a frictionless horizontal table at 1.5m/s2.
Find the mass of object m1
A. 0.61kg B...
Homework Statement
Note: My textbook and first language is french, I am sorry if I mistranslated some terms.
A friction-less rope goes around the fix pulley A. At one side of the rope, there is a mass M1. On the other side, there is a pulley of mass M2. Another friction-less rope goes...
could you please tell me how can the accelaration of masses m1 and m2 can be different.
i am in a great necessity.so please explain me how can the two strings of the two sides of the lower pulley have different accelarations?
Homework Statement
Two masses are connected by a light string that goes over a light, frictionless pulley, as shown in the figure. The 8.7-kg mass m1 is released and falls through a vertical distance of h = 1.09 m before hitting the ground. Use conservation of mechanical energy to determine...
Homework Statement
Need some serious help with this one :O
A box with a weight WA hangs in pulleys ,(see figure 1). Find the force to pull A up with constant speed and calculate the work which the tractive force F produces ( with the movement of s) and also the work and tractive force...
Homework Statement
If F = 8.0 N and M = 1.0 kg, what is the tension in the connecting string? The pulley and all surfaces are frictionless.
Homework Equations
F=ma
The Attempt at a Solution
8-T=2a (2kg block)
T - 1cos10? = 1a (for the 1kg block. I got stuck here, the angle threw...
Homework Statement
John (mass 80) rests on top of a light cube (mass = 0). A light rope passes horizontally from him over the front edge, and vertically down to Brian (mass 60kg) who hangs in contact with the front face as shown. The cube is on a horizontal surface and there is no friction...
Homework Statement
9) A 15 kg wedge is pushed along a frictionless surface. There is no friction between the wedge and the block. What force, F, is required to keep the block from sliding up or down the wedge?
See attachment for diagram.
10) Find the tension, T.
See attachment for diagram...
Homework Statement
2 blocks that have the same mass are connected by a string and passed over a pulley. The angle made by the horizontal plane and the ramp is 30 degrees. 1 of the blocks is dangling off the edge of the ramp while the other block is placed on the ramp. If neither block moves...
Homework Statement
Block B, with mass 5.00kg, rests on block A, with mass 8.00kg , which in turn is on a horizontal tabletop. There is no friction between block A and the tabletop, but the coefficient of static friction between block A and block B is 0.750. A light string attached to block A...
Hi! First Time Poster.
Thank you for helping me with my problem!
Homework Statement
A 28.3-kg block (m1) is on a horizontal surface, connected to a 5.5-kg block (m2) by a massless string as shown in the Figure. The pulley is massless and frictionless. A force of 208.9 N acts on m1 at...
Homework Statement
http://img813.imageshack.us/img813/594/75309500.png
http://img813.imageshack.us/img813/7166/51848816.png
I have to find acceleration to calculate how long it takes the heavier box to reach the end of the table.
Homework Equations
The Attempt at a Solution...
Homework Statement
Two unequal masses are connected by a light cord passing over a smooth pulley. State the gravitational potential energy \DeltaU(> or < or = 0) and the kinetic energy \DeltaK(> or < or = 0) of the system after the masses are released from rest?
Homework Equations...
Hi everybody, I was doing my physics homework but I found that I cannot figure out how to do it, here is the question:
http://imageshack.us/photo/my-images/202/phyl.jpg/"
I don't quite understand how to calculate the torsional spring constant, so explanation on part a is enough:D Thanks...
Homework Statement
See the picture
Homework Equations
The Attempt at a Solution
This is a very difficult, can anyone guide me step by step to finish this question.
First, let start with part(a)
In order to find the ratio, it seems we need to have the motion equations first...
Homework Statement
A simple Atwood machine composed of a single pulley and two masses, m1 and m2 is on an elevator. When m1= 44.7kg and m2=45.3kg, it takes 5.00s for mass m2 to descend exactly one meter from rest relative to the elevator. What is the elevator's motion? (That is, is it moving...
Homework Statement
A 0.840- kg glider on a level air track is joined by strings to two hanging masses. As seen in the figure, the mass on the left is 4.85 kg and the one on the right is 3.62 kg The strings have negligible mass and pass over light, frictionless pulleys. Find the acceleration of...
Consider the massless pulley connected by a spring at the pivot. What is the displacement x at equilibrium after the mass m has been added? Determine x in terms of m, g, and k.
I drew picture of the problem and tried to work it out in the pic below. The answer should be x = 4mg/k, but I don't...
Homework Statement
Two clay pots (m1 = 6 kg, m2 = 3 kg) joined together by a light string rest on a table. The frictional coefficient between the pots and the table is 0.35. The pots are also joined to a suspended mass (m3 = 4kg) by a string of negligible mass passed over an ideal pulley as...