A 65 kg person jumps from a window to a fire net 21 m below, which stretches the

Question

A 65 kg person jumps from a window to a fire net 21 m below, which stretches the net 1.2 m . Assume that the net behaves like a simple spring.

Part A

Calculate how much it would stretch if the same person were lying in it.

Express your answer to two significant figures and include the appropriate units.

x = (Value) (Units)

Part B

How much would it stretch if the person jumped from 36 m ?

Express your answer to two significant figures and include the appropriate units.

x = (Value) (Units)

x = (Value) (Units)

Explanation / Answer

let k is the spring constant

A) gain in elastic pitential energy = loss gravitational potentail energy

(1/2)*k*x^2 = m*g(h+x)

k = 2*m*g*(h+x)/x^2

= 2*65*9.8*(21+1.1)/1.2^2

= 19552 N/m

now Apply, m*g = k*delta_x

==> delta_x = m*g/k

= 65*9.8/19552

= 0.0326 m  <<<<<<<<<<-------------Answer

B) Again Apply,

(1/2)*k*x^2 = m*g*(h+x)

(1/2)*19552*x^2 = 65*9.8*(36+x)

on solving the equation

we get

x = 1.56 m <<<<<<<<<<-------------Answer

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