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Bethany, who weighs 560 N, lies in a hammock suspended by ropes tied to two trees. The left rope makes an angle of 45∘ with the ground; the right one makes an angle of 30∘.

A)

Find the tension in the left rope.

Express your answer with the appropriate units.

B)

Find the tension in the right rope.

Express your answer with the appropriate units.

Respuesta :

Answer:

[tex]T_1=409.95\ N\\T_2=502.08\ N[/tex]

Explanation:

Conditions for Equilibrium

There are three forces applied to Bethany: T1 to the right making an angle of 30° with the ground, T2 to the left making an angle of 45° with the ground, and the weight W down the y-axis. Since the system is assumed to be at rest, the forces must be in equilibrium.

Please refer to the image below.

In the y-axis:

[tex]T_{1y}+T_{2y}=W[/tex]

The projections of the tensions in the vertical direction are

[tex]T_{1y}=T_1sin30^o[/tex]

[tex]T_{2y}=T_2sin45^o[/tex]

Thus, replacing into the first equation:

[tex]T_1sin30^o+T_2sin45^o=W\text{...........[1]}[/tex]

Now for the x-axis

[tex]T_{1x}-T_{2x}=0[/tex]

[tex]T_{1x}=T_{2x}[/tex]

The components of T1 and T2 in the horizontal direction are

[tex]T_{1x}=T_1cos30^o[/tex]

[tex]T_{2x}=T_2cos45^o[/tex]

Replacing

[tex]T_1cos30^o=T_2cos45^o[/tex]

Solving for T1

[tex]\displaystyle T_1=\frac{T_2cos45^o}{cos30^o}[/tex]

[tex]T_1=0.8165T_2[/tex]

Replacing in [1]

[tex]0.8165T_2sin30^o+T_2sin45^o=560[/tex]

Computing the trigonometric values and simplifying

[tex]1.1154T_2=560[/tex]

Solving

[tex]\boxed{T_2=502.08\ N}[/tex]

And therefore

[tex]T_1=0.8165T_2=0.8165\cdot 502.08\ N[/tex]

[tex]\boxed{T_1=409.95\ N}[/tex]