Question

An intrepid physics student decides to try bungee jumping. She obtains a cord that is 9.39 m long and has a spring constant of 8.00 ✕ 10²N/m. When fully suited, she has a mass of 72.6 kg. She looks for a bridge to which she can tie the cord and step off. Determine the minimum height of the bridge that will allow her to stay dry (that is, so that she stops just before hitting the water below). Assume air resistance is negligible.

Answer 1

Given data The spring constant is 800 Nm The mass is m = 726 kg The height is h=939+x Let us consider, x'be the extension in the cord after the jumping of the student. So, potential energy lost by the student during jumping PE mgh = mg(9.39+x) Again, this energy will be stored in the spring due to its expansion. And this is Equalizing the above two equations mg (9.39+x) l (72.6)(9.8) (9.39+x) (800)x -400x +6680.79+711.48x-0 r-5.07 The minimum height is h 9.39 + x = 9.39+5.07 = 14.46 m