Tarzan, mass 85kg swings down from a tree limb on the end of a 20m vine. his feet touch the ground 4.0m below the limb.

Question

A. how fast is Tarzan moving when he reaches the ground?

B. Does your answer depend on Tarzan's mass?

C. Does your answer depend on the length of the vine?

It doesn't even give you a proper length, it only says 4.0m below the ground, how am I supposed to know how much that is?

Need help with the overall calculations and B. And C.

Answer 1

Strictly speaking, his speed at the bottom would not depend upon where his feet are, it would depend upon how far his center of mass dropped. You also need to know where he gripped the vine. Maybe he did not hold it at the very end.

They also do not say if the vine was initially horizontal. This information is also needed.

They probably expect you to assume
V(bottom)^2/2 = g (20 + 4 meters)

It is not a well defined problem

Answer 2

(a)We know at equilibrium,
Potential energy =kinetic energy
=>m*g*h=1/2*m*v^2
=>m*g*h*2=m*v^2
=>(m*g*h*2)/m=v^2
=>2*g*h=v^2
=>sqrt(2*g*h)=v
=>v=sqrt(2*g*h)
Now putting the values,
v=sqrt(2*10*4)
=>sqrt(80)
=>8.944m/s^2 OR (after rounding off) 9m/s^2
Therefore he was moving with 9m/s^2 speed /velocity when he reached the ground. =Ans
(b) No, our answer does not depend upon his mass, because it gets cancelled in the process.
(c) No, our answer does not depend on the length of the vine either, because it is not required in the process.
Hope it helps you, if it does, just pray, that I may succeed in my boards this year with brilliant marks.. Please😊😊

Answer 3

The solutions were cleared

Answer 4

Using the kinematics formula:
v^2 = Vo^2 +2ad
Vf^2 = 2(9.80)(4.0)
Vf^2 = 78.4
V = 8.9 m/s