Can you me with Newtons 3rd Law

AI Thread Summary
To find the tension force and acceleration in a pulley system with two masses, start by identifying the net force acting on the system. For a frictionless pulley with a 4kg mass and a 3kg mass, the net force can be calculated as the difference in weight, resulting in a force of 10N. Using Newton's second law (F=ma), the total mass (7kg) allows you to determine the acceleration. The tension in the rope can be calculated using the formula for each mass, ensuring that the values are consistent. This approach clarifies the relationship between tension, acceleration, and the forces acting on the masses.
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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