# Work and energy

Jane, whose mass is 50.0kg, needs to swing accross a river(having width of D) filled with man-eating crocodiles to save Taezan from danger. She must swing into a wind exerting a constant horizontal force F on a vine having a length L and initially making an angle (theta) with the vertical.

Taking D=50.0m F=110 N L=40.0m and theta= 50.0 degrees

(a) With what minimum speed must Jane begin her swing in order to just make it to the other side? (b) Once the rescue is complete, Tarzan and Jane must swing back across the river . With what maximum speed must they begin their swing? Assume Tarzan has a mass of 80.0kg

the answers are (a) 6.15 m/s (b) 9.87m/s

I need to know how to get those answers.

This problem is word for word out of a physics 1 textbook and the answers are from the back of the book; therefore, have been verified.

Solve by E(final) = E (initnial)

Using PEg or KE or both

Thank you

https://brainmass.com/physics/system-work/work-and-energy-9472

#### Solution Preview

Hello and thank you for posting the question to braimass.

<br>

<br>I got 6.13 and 9.89 as my final answers, and it is due to trancuation of the numbers.

<br>anyway, I suggest that before you open the solution which is contained in the files below (one in PDF and one in MS- word format) try to solve the problem using these hints:

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<br>1. The vine is not suspended right above the center of the ...

#### Solution Summary

The 4 pages solution gives describes in detail the procedure to solve this problem, including full drivations and figures.