Acceleration of two masses and tension.

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SUMMARY

The discussion centers on calculating the acceleration of two masses and the tension in a string in a frictionless environment. The user is attempting to solve a physics problem involving a 3 kg mass and a 5 kg mass, with the latter on a ramp inclined at 40 degrees. Key equations discussed include the free body diagram analysis and the normal force calculation, which is determined as FN = 42.43N using FN = mg x cos(θ). The user seeks guidance on how to proceed with finding the tension in the string.

PREREQUISITES
  • Understanding of Newton's laws of motion
  • Knowledge of free body diagrams
  • Familiarity with trigonometric functions in physics
  • Basic concepts of tension in strings and forces in equilibrium
NEXT STEPS
  • Calculate the tension in the string using T1 for the 3 kg mass
  • Explore the concept of acceleration in a two-mass system
  • Review the effects of inclined planes on mass acceleration
  • Study examples of frictionless systems in classical mechanics
USEFUL FOR

Students studying physics, particularly those focusing on mechanics, as well as educators looking for problem-solving strategies related to tension and acceleration in frictionless systems.

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Homework Statement


Hi guys, got a bit of a tough problem that i can't seem to solve.

What is the acceleration of two masses and the tension in the string if both surfaces are friction less.


http://img376.imageshack.us/img376/5889/physics.jpg


Homework Equations





The Attempt at a Solution



Now i had another example that i tried to follow but, in that one the force of friction is 9N. I tried to make the following eqn

m2a = -T-m2gsin40 - ( this is where i got stuck, i don't know what to subtract as there is no force given.)

could someone give me an idea where to start? thanks.
 
Last edited by a moderator:
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Think about (and set up) your free body diagram. You know that tension is an internal force (i.e. it doesn't happen by itself, something causes tension). And you know your system is isolated. Just imagine intuitively, what's stopping the 5kg block from sliding down the ramp if the ramp is very slippery? Is there anything stopping it?

It might also be helpful to think about this system as two dangling weights (i.e. with no surface, therefore no friction) and then think about what the surface does.
 
Him ok so i don't know if this is right but i was able to find out FN by doing this

FN = mg x cos[tex]\vartheta[/tex] = 3kg(9.8m/s2) * cos30
FN = 42.43N

Now from here would i go on to find T1 for the 3kg mass?
 
Last edited:

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