# Balanced moments and levers

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• Created by: blloob1
• Created on: 04-05-14 11:32
• Balanced moments and levers
• ballanced moments
• If the anti clockwise moments are equal to the clockwise moments the object wont turn
• for a balanced moment the total anticlockwise= total clockwise moments
• example 1 you younger brother weighs 200n and sits 2 meatures away from the pivot of a seeesaw
• if you weigh 700n where should you sit to balence the seesaw
• 300*c=700*y
• 600/700 =0.85
• y=0.86m
• Example 2 a 6m long steel girder weighing 1000n rests horizontally on a pole 1m from one end.
• what is the tension in a supporting cable attached virtically to the other end
• the tension in the cable makes it sound harde then it actualy is but the girdes weight is balanced  by the tension force in the cable
• anticlockwise moment (due to weight)= clockwise moment (due to cable tension)
• levers
• levers use theidea of balanced moments to make it easier for us to do work
• the moment needed for us to do work= force * distance from the pivot so the amount of force needed to do work depends on the distance the force is applied from the pivot
• levers increase the distance from the pivot at which the force is applied
• this means less force is neaded to create the same moment
• 1000*2=t*5
• anticlockwise moment (due to weight)= clockwise moment (due to cable tension)
• 2000=5T
• T=400n