Mechanics Equlibrium question:

[laurasanchezr]

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My question is about the illustration used to explain this problem:

In the fig. below, a block of mass 40kg is held in place by two ropes exerting equal tension forces. If cos theta= 2/3 whats the tension in each rope?

I've attached the illustration.
My question is: why did they label Ft Sin theta in the horizontal and Ft cos theta for the vertical forces..this is totally throwing me off.

 

[SOOyC52H1Sof]

My question is about the illustration used to explain this problem:

In the fig. below, a block of mass 40kg is held in place by two ropes exerting equal tension forces. If cos theta= 2/3 whats the tension in each rope?

I've attached the illustration.
My question is: why did they label Ft Sin theta in the horizontal and Ft cos theta for the vertical forces..this is totally throwing me off.

You may be over thinking this question. Look at the angle they picked.

Sin Θ=Opposite/Hypotenuse

Since the Hypotenuse=Ft

then using algebra, Opposite= Ft *Sin Θ


Like wise, if they picked the opposite interior angle as their angle instead, the horizontal would have been Ftcos Θ, b/c
cos Θ=adjacent/hypotenuse

 

[laurasanchezr]

You're totally right it was simple, and it makes total sense now.

Thanks! 🙂

 

[SN2ed]

Thread closed. These kinds of questions belong in the Study Q&A forum only.