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

AI Thread Summary
A mass of 2kg is suspended from a 40cm string, held 20cm horizontally from the vertical, requiring a horizontal force to maintain equilibrium. The problem involves using trigonometry to analyze the forces acting on the mass. By forming a right triangle with the string length and horizontal distance, the angle can be determined, allowing for the calculation of tension and horizontal force components. The vertical component of tension equals the weight of the mass, while the horizontal component equals the applied force. The final results show tension at 22.6N and horizontal force at 11.3N, confirming the calculations.
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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