greater than 0 degrees but less than 90 degrees
0 degrees (rope is horizontal)
I know the answer is A. I found this question in practice problems for midterms.
Now, I was trying to prove it:
horizontal pulling: F=ukmg.
greater than 0 degrees but less than 90 degrees:
Horizontal component: uk(mg-sinthetaF) (Let F be magnitude of force.)
Vertical component: costhetaF
(Pythagoras) and (sin^2theta+cos^2theta=1)
How do I prove 0.81mg-1.8sinthetaF+F^2 > 0.9mg?