Jane, whose mass is 49.5 kg, needs to swing across a river (having width D ) fil

Question

Jane, whose mass is 49.5 kg, needs to swing across a river (having width D) filled with person-eating crocodiles to save Tarzan from danger. She must swing into a wind exerting constant horizontal force

on a vine having length L and initially making an angle ? with the vertical (see below figure). Take D = 51.0 m,

L = 40.0 m, and ? = 45.0

Jane, whose mass is 49.5 kg, needs to swing across a river (having width D) filled with person-eating crocodiles to save Tarzan from danger. She must swing into a wind exerting constant horizontal force F rightarrow on a vine having length L and initially making an angle ? with the vertical (see below figure). Take D = 51.0 m, F rightarrow = 106 N, L = 40.0 m, and ? = 45.0 degree . With what minimum speed must Jane begin her swing to just make it to the other side? (If Jane can make it across with zero initial velocity, enter 0.) Once the rescue is complete, Tarzan and Jane must swing back together across the river. With what minimum speed must they begin their swing? Assume that Tarzan has a mass of72.8 kg.

Explanation / Answer

D = L*sin theta + L sin phi

51 = 40 * 1/sqrt(2) + 40 sin phi

phi = 34.6 degrees

Energy lost = energy gained

F*s= 1/2 mv^2 + mg(h2-h1)

106*51 = 1/2 * 49.5 *v^2 + 49.5*9.8*(Lcos34.6 - L cos 45)

v = 11.29 m/s

(b) 106 * 51 + 1/2 (49.5+72.8)*v^2 = 122.3 * 9.8*(Lcos34.6 - L cos 45)

v = 1.6 m/s

Related Questions

Navigate

• Browse (All)
• Browse J
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.