Three boxes on different inclines

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SUMMARY

The discussion focuses on a physics problem involving three boxes on different inclines, specifically box A (8.0kg), box B (2.0kg), and box C (9.0kg). The user initially calculated an acceleration of 1.57 m/s² to the right but later corrected it to 0.57 m/s² after realizing the components of gravity were miscalculated due to reversing cosine and sine. The problem also involves calculating the coefficient of static friction and the tension in the strings, with a given coefficient of kinetic friction of 0.050.

PREREQUISITES
  • Understanding of Newton's second law (fnet = ma)
  • Knowledge of trigonometric functions (sine and cosine)
  • Familiarity with concepts of friction (static and kinetic)
  • Basic mechanics involving pulleys and inclined planes
NEXT STEPS
  • Calculate the coefficient of static friction for box A to remain motionless on the incline.
  • Determine the tension in the strings connecting boxes A and C to box B.
  • Explore the effects of friction on the acceleration of the system with varying coefficients.
  • Review the principles of inclined plane physics and pulley systems for deeper understanding.
USEFUL FOR

Students studying physics, particularly those focusing on mechanics and dynamics involving forces, inclines, and friction. This discussion is beneficial for anyone tackling similar problems in homework or exams.

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Homework Statement


There are three boxes, box B weighs 2.0kg, and is sitting on a flat surface. To the left is box A, tied to box B. Box A weighs 8.0kg and is sitting on an incline 110 degrees from the horizontal (or 70 depending on the location of the measurement). To the right of box B is box C, sitting on an angle 130* from the horizontal, tied to box B. It weighs 9.0kg. All ropes are supported by pulleys.
a)assuming no friction, calculate acceleration of the system
b) calculate coefficient of static friction to remain motionless
c) coefficient of kinetic friction is 0.050, calculate acceleration and tension in both strings


Homework Equations


fnet = ma


The Attempt at a Solution


I managed to get an acceleration of 1.57m/s to the right, but I feel like it's wrong, I can't seem to get the components of gravity to work out right, I think I'm doing something wrong there.
I haven't got to B or C because I don't want to go through the entire thing with incorrect numbers.
 
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Update : turns out I had cosine and sine reversed so my components were in the wrong direction, I got an acceleration of 0.57 m/s/s which is much more reasonable.
 

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