Can you me with Newtons 3rd Law

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SUMMARY

The discussion focuses on calculating tension force and acceleration in a frictionless pulley system involving two masses: a 4kg box and a 3kg box. The net force acting on the system is determined to be 10N, leading to an overall acceleration of 1.43 m/s² when applying Newton's second law (fnet = ma). The tension in the rope can be calculated using the formulas T = m1(g + a) for the lighter mass and T = m2(g - a) for the heavier mass, ensuring both tension values are equal for verification.

PREREQUISITES
  • Understanding of Newton's Laws of Motion, specifically Newton's Third Law
  • Basic knowledge of force calculations (fnet = ma)
  • Familiarity with gravitational force equations (fg = mg)
  • Concept of frictionless systems and their implications in physics
NEXT STEPS
  • Study detailed examples of tension calculations in pulley systems
  • Learn how to apply Newton's Second Law in various scenarios
  • Explore the effects of friction in pulley systems and how to calculate it
  • Investigate advanced problems involving multiple pulleys and masses
USEFUL FOR

Students studying physics, particularly those focusing on mechanics and dynamics, as well as educators seeking to explain tension and acceleration in pulley systems.

slobodan48
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how do you find the Tension force,acceleration,magnitude.
Its those questions where you have pullys,boxes pushing each other...
I am really confused for the 3rd law
 
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slobodan48 said:
how do you find the Tension force,acceleration,magnitude.
Its those questions where you have pullys,boxes pushing each other...
I am really confused for the 3rd law

Do you have a specific example? I'd hate to just vapidly repeat the definition of the 3rd law, which you can easily find anywhere and everywhere...
 
Two masses are places in a frictionless pulley system.Solve for the acceleration and tension forces.
1st box is 4kg and the other is 3kg

well i know,
fnet=ma
fg=mg
ff=muFn
 
You could start by saying that there is a net, unbalanced force of 10N (For GCSE level thought - or you can do 9.81m/s/s, if you like), pulling one up and one down.
This is accelerating both the masses (7kg total), use your formula to find the acceleration.
The tension will be ml times (g + this acceleration) for the light mass and also mh times (g- this acceleration) for the heavy mass. Those two values should be the same, natch - as a check.
etc etc - you can put in the numbers
 

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