Statics - mass attached to a string. Find forces acting to keep in equilibrium

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SUMMARY

The discussion focuses on solving a statics problem involving a mass attached to a string. A 2 kg mass is suspended from a 40 cm string, held at a horizontal distance of 20 cm from the vertical. By applying trigonometric principles, participants determined the tension in the string to be 22.6 N and the horizontal force required to maintain equilibrium to be 11.3 N. The solution involves analyzing the right-angled triangle formed by the string and the horizontal distance.

PREREQUISITES
  • Understanding of basic trigonometry, specifically right-angled triangles.
  • Knowledge of Newton's laws, particularly the equilibrium of forces.
  • Familiarity with tension in strings and forces acting on masses.
  • Ability to apply vector components to solve for unknown forces.
NEXT STEPS
  • Study the principles of static equilibrium in physics.
  • Learn about vector decomposition in force analysis.
  • Explore trigonometric functions and their applications in physics problems.
  • Practice similar statics problems involving tension and forces in equilibrium.
USEFUL FOR

This discussion is beneficial for physics students, educators, and anyone interested in understanding the principles of statics and force analysis in mechanical systems.

HM10
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Hey guys, this is my first time posting and I really need your help.

I'm stuck on this question:
A light inextensible string of length 40cm has its upper end fixed at a point A, and carries a mass of 2kg at its lower end. A horizontal force applied to the mass keeps it in equilibrium, 20cm from the vertical through A. Find the magnitude of this horizontal force and the tension in the string.

From this I think I only know one force which would be 2g. I also know the lengths but what to do with them?!
I'm guessing I have to use trigonometry? I'm really clueless and don't know where to start. I can't even think of what the diagram would look like. I'd appreciate any help!

I tried making a triangle, with sides 0.2,0.4 and 2g. Don't know how this will help tho :(

Thanks in advance
 
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Hi HM, welcome to PF.
40 cm, 20 cm and vertical forms a right angled triangle. From that you can find the angle between the horizontal and the tension in the string. Then find the component of T in the vertical and horizontal direction. Equate the vertical component to mg and the horizontal component to force. And solve for F and T.
 
rl.bhat said:
Hi HM, welcome to PF.
40 cm, 20 cm and vertical forms a right angled triangle. From that you can find the angle between the horizontal and the tension in the string. Then find the component of T in the vertical and horizontal direction. Equate the vertical component to mg and the horizontal component to force. And solve for F and T.

Thanks a lot for the help.I followed your instructions and got T=22.6N and F=11.3N which are the answers in the back!

Cheers :)
 

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