Register to reply

Static Equilibrium Problem Dealing with Torque

by PeachBanana
Tags: dealing, equilibrium, static, torque
Share this thread:
PeachBanana
#1
Mar30-12, 08:41 PM
P: 191
1. The problem statement, all variables and given/known data

The figure shows a model of a crane that may be mounted on a truck. A rigid uniform horizontal bar of mass = 90.00 kg and length = 5.200 m is supported by two vertical massless strings. String A is attached at a distance = 1.600 m from the left end of the bar and is connected to the top plate. String B is attached to the left end of the bar and is connected to the floor. An object of mass = 3000 kg is supported by the crane at a distance = 5.000 kg from the left end of the bar.

Throughout this problem, positive torque is counterclockwise and use 9.807 m/s^2 for the magnitude of the acceleration due to gravity.


Find the tension in string A.

2. Relevant equations

This problem lets you use hints and it suggested I use the following equation with having the Tension in String "B" as the origin.


3. The attempt at a solution

Tension A(1.6000m) - (90.00 kg)(9.807 m/s^2) 1/2(5.200 m) - (3000 kg)(9.807 m/s^2)(5.000 m) = 0

I don't understand the "1/2" part in front of the length mass one. Is that because of where it is placed or its moment of inertia?
Attached Thumbnails
BarSuspended.jpg  
Phys.Org News Partner Science news on Phys.org
Experts defend operational earthquake forecasting, counter critiques
EU urged to convert TV frequencies to mobile broadband
Sierra Nevada freshwater runoff could drop 26 percent by 2100
PhanthomJay
#2
Mar30-12, 09:39 PM
Sci Advisor
HW Helper
PF Gold
PhanthomJay's Avatar
P: 6,043
If the weight of the 90 kg beam is uniformly distributed over its length, where does its resultant load act?
PeachBanana
#3
Mar30-12, 10:27 PM
P: 191
I'm sorry, I'm not sure what you mean by resultant load.

PhanthomJay
#4
Mar31-12, 09:57 AM
Sci Advisor
HW Helper
PF Gold
PhanthomJay's Avatar
P: 6,043
Static Equilibrium Problem Dealing with Torque

Quote Quote by PeachBanana View Post
I'm sorry, I'm not sure what you mean by resultant load.
If a uniform beam that is 2 m long has a mass of 0.5 kg/m, its total mass is 1 kg and it's resultant or total weight is 9.8 N. It can be represented as a single force of 9.8 N acting at its center of gravity.


Register to reply

Related Discussions
Problem dealing with Equilibrium & Torque Introductory Physics Homework 4
Length of bar needed to lift a crate(Torque, static equilibrium problem) Introductory Physics Homework 1
Static equilibrium and torque problem Introductory Physics Homework 5
Torque/Static Equilibrium/Forces problem... Introductory Physics Homework 4
Static Equilibrium/Torque/Force problem General Physics 0