26) After a skiing accident, your leg is in a cast and sup-ported in a traction device, as shown in FIGURE 6-43. Find the magnitude of the force F> exerted by the leg on the small pulley. (By Newton's third law, the small pulley exerts an equal and opposite force on the leg.) Let the mass m be 2.27 kg.

26 After a skiing accident your leg is in a cast and supported in a traction device as shown in FIGURE 643 Find the magnitude of the force Fgt exerted by the le class=

Respuesta :

[tex]F=38.57\text{ Newtons}[/tex]

Explanation

Step 1

free body diagram

Step 2

now, let's analyze the forces

a) in y

Newton's first law says that if the net force on an object is zero ( Σ F = 0 \Sigma F=0 ΣF=0\Sigma, F, equals, 0)

so, as the leg is in rest

[tex]\begin{gathered} \sum ^{\square}_{\text{ y}}=_{}0 \\ T_1\sin 30-T_2sen\text{ 30=0} \end{gathered}[/tex]

let

m= 2.27 Kg , so

[tex]\begin{gathered} \text{weigth}=m\cdot g \\ \text{weigth}=2.27\operatorname{kg}\cdot9.81m/s^2 \\ \text{weigth}=22.2687\text{ N} \end{gathered}[/tex]

hence

[tex]\begin{gathered} T_2=weigth \\ T_2=22.2687 \end{gathered}[/tex]

[tex]\begin{gathered} T_1\sin 30-T_2sen\text{ 30=0} \\ T_1\sin 30-(22.2687)sen\text{ 30=0} \\ T_1\sin 30-(22.2687)sen\text{ 30=0} \\ T_1\sin 30-11.13435=0 \\ \text{add}11.13435\text{ in both sides} \\ T_1\sin 30-11.13435+11.13435=0+11.13435 \\ T_1\sin 30=11.13435 \\ \text{divide both sides by sin 30} \\ \frac{T_1\sin30}{\sin\text{ 30}}=\frac{11.13435}{\sin \text{ 30}} \\ T_1=22.2687\text{ Newtons} \end{gathered}[/tex]

b) now in x ( horizontally)

[tex]\begin{gathered} \sum ^{\square}_{\text{ x}}=_{}0 \\ -F+T_1cos30+T_2cos\text{ 30=0} \\ \text{add F in both sides} \\ -F+T_1cos30+T_2cos\text{ 30+F=0}+F \\ F=T_1cos30+T_2cos\text{ 30} \\ \text{replace} \\ F=(22.2687)cos30+(22.2687)_{}cos\text{ 30} \\ F=38.57\text{ Newtons} \end{gathered}[/tex]

therefore, the answer is

[tex]F=38.57\text{ Newtons to the left}[/tex]

I hope this helps you

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