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| Insert description of apparatus, its component, what it is demonstrating. | Two small lead balls are supported on a cross-beam which is suspended by a fine wire(glass) to form a torsion pendulum. 2 Large lead spheres are placed opposite the small balls to exert a force onto the suspended system. |
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| '''Demonstration:''' The objective of this experiment is to determine G. F = (GmM)(r^-2). Two small lead balls, each of mass m, are supported on a T-shaped form which is suspended by a fine wire to form a torsion pendulum. Large lead spheres each of mass M are placed opposite the small balls, exerting a torque on the moving system. The system is allowed to come to rest, and the equilibrium position is shown by a laser beam reflected to a scale. The large lead balls are then shifted to give a torque in the opposite direction. The approach to the new equilibrium is a damped simple harmonic motion and requires over an hour and a half to come to rest. |
'''Demonstration:''' |
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| The two smaller masses have a mass of m=38g and are made of lead. They are suspended on a cross-beam torsion wire and have a distance of d=50.0mm for center-to-center of each ball. The two larger masses are made of lead too and have a mass of M=1.5Kg | |
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| Insert description of demonstration, how is the demonstration preformed. | The objective of this experiment is to determine G. F = (GmM)(r^-2). The two large lead spheres are placed opposite the small balls, which will exert a torque and move cross-beam torsion wire system. The system is now allowed to come to a new equilibrium position which is shown by a laser beam reflected off the a small mirror that is attracted to the cross-beam torsion wire system. The reflected laser dot will be on the opposite wall and the motion of the cross-beam can be observed and measured. Allowed the system to come to an equilibrium position. The large lead balls are then shifted to the other smaller lead ball to give a torque in the opposite direction. The cross-beam torsion wire system is then aloud to find a new equilibrium as it damped out in a simple harmonic motion. Full damping requires over an hour and a half. |
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| 1. [attachment:CavendishManual.pdf Cavendish Manual (pdf)] |
Cavendish Balance, 1L10.30
Location:
Cabinet: Mechanic (Will be permanently installed in lecture halls)
Bay: {B12}
Shelf: "1"
attachment:CavendishBalance.jpg (photo from Pasco online)
Description:
Two small lead balls are supported on a cross-beam which is suspended by a fine wire(glass) to form a torsion pendulum. 2 Large lead spheres are placed opposite the small balls to exert a force onto the suspended system.
Equipment:
Location
ID Number
Cavendish Balance
ME, B12, 1
1L10.30
Laser
...
...
Setup:
- Currently Setup requires a 48 hour notes before lecture. Once there installed within the room this condition maybe lifted.
- Make sure the Cavendish Torsion Balance is level on a bench or platform that has no vibration.
Cautions, Warnings, or Safety Concerns:
- The Large Masses are made of Lead and weight about 1.5Kg
- The Torsion Balance inside the Cavendish is very delicate and can break.
Demonstration:
The two smaller masses have a mass of m=38g and are made of lead. They are suspended on a cross-beam torsion wire and have a distance of d=50.0mm for center-to-center of each ball. The two larger masses are made of lead too and have a mass of M=1.5Kg
The objective of this experiment is to determine G. F = (GmM)(r^-2). The two large lead spheres are placed opposite the small balls, which will exert a torque and move cross-beam torsion wire system. The system is now allowed to come to a new equilibrium position which is shown by a laser beam reflected off the a small mirror that is attracted to the cross-beam torsion wire system. The reflected laser dot will be on the opposite wall and the motion of the cross-beam can be observed and measured.
Allowed the system to come to an equilibrium position.
The large lead balls are then shifted to the other smaller lead ball to give a torque in the opposite direction. The cross-beam torsion wire system is then aloud to find a new equilibrium as it damped out in a simple harmonic motion. Full damping requires over an hour and a half.
attachment other photos |
attachment other photos |
attachment other photos |
attachment other photos |
References:
[http://store.pasco.com/pascostore/showdetl.cfm?&DID=9&Product_ID=1655&groupID=306&Detail=1 Pasco]
[attachment:CavendishManual.pdf Cavendish Manual (pdf)]
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