Moments/torque in relation to laws of motion

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SUMMARY

This discussion focuses on the relationship between torque and Newton's laws of motion, specifically how torque (τ = Fd) relates to linear force (F = ma). The conversation highlights that when a force is applied to one end of a rod pivoted at the center, the other end moves due to the attractive forces between the atoms in the rod, which transmit the force. It also explains that if the applied force exceeds the strength of these atomic bonds, the rod will break, demonstrating the principles of tension and compression in beams.

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  • Understanding of basic physics concepts such as force, mass, and acceleration.
  • Familiarity with torque and its formula (τ = Fd).
  • Knowledge of moment of inertia and angular acceleration.
  • Basic principles of tension and compression in materials.
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  • Study the relationship between torque and moment of inertia in rotational dynamics.
  • Explore the concepts of tension and compression in structural engineering.
  • Learn about the failure modes of materials under stress.
  • Investigate real-world applications of torque in mechanical systems.
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Kinhew93
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I've just started learning about torque, and understand that tau=Fd, but wondered how this relates to F=ma.

For example if there is a rod with a pivot in the middle (say a nail), when one end is pushed down, why does the other end move up? Where is the force that causes the end to move up coming from?

thanks :)
 
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The force that moves the other end is the attractive forces holding the atoms/molecules of the rod together. The force applied on one end is transferred to the other via these bonds. Hence, if you strike the end of the rod hard enough you will apply too much acceleration for the bonds to hold and it will break, while the other end barely moves at all.
 
Kinhew93 said:
I've just started learning about torque, and understand that tau=Fd, but wondered how this relates to F=ma.

The "equivalent" expressions would be...

Force = mass * acceleration

Torque = moment of inertia * angular acceleration

For example if there is a rod with a pivot in the middle (say a nail), when one end is pushed down, why does the other end move up? Where is the force that causes the end to move up coming from?

Take a look at the forces in a beam. The top of the beam is in tension and the bottom of the beam is in compression. If these forces are unbalanced by the application of a new force the beam will accelerate (eg it will start to rotate or if already rotating it will rotate faster).

and as Drakkith said..if the forces are too large the beam will fail.
 

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