# Potential Energy and Conservation of Energy Question 1.?

Tarzan, who weighs 688N, swings from a cliff at the end of a convenient vine that is 18m long. From the top of the cliff to the bottom of the swing, he descends by 3.2m The vine wll break if the force on it exceeds 950N. (a) Does the vine break? (b) If no, what is the greatest force on it during the swing? If yes, at what angle with the vertical does it break?

Relevance

Conservation of energy: 0.5*m*v^2=m*g*h

m=Tarzan's mass, v=his speed, g=gravitational constant (ca.9.8), h=heigth of fall

Centripetal force= Fc=m*v^2/r whereby r = radius of curve=18m.

Combining the two equations yields Fc=2*m*g*h/r = 2*688*3.2/18=244.6 N

So on top of the force exerted by his weigth = 688N the centripetal force on the vine Going through part of an circle adds 244.6N.

Together 932.6N which is also the greatest force.

I am relieved, our hero will live. Answer=no

• Login to reply the answers
• Hint: The tension in the vine is greatest at the lowest point of the arc, where T is Tarzan's weight plus the centripetal force he experiences.

• Login to reply the answers