Hey i have been having trouble with this last part of a long question, I only ne
ID: 1774699 • Letter: H
Question
Hey i have been having trouble with this last part of a long question, I only need help with 15, but i included the others to give you some values. Thanks!
A student who just got 10/10 on a Physics midterm decides to try bungee jumping as a reward. He attaches an elastic bungee cord to his ankles and happily jumps off a tall bridge across a river. He ends up barely touching the water before the cord jerks him back up. The bungee cord has an unstretched length of =5.5 m and a spring constant of k=20 N/m; the distance from the bridge to the water surface is L=51 m. Eventually you will be asked to find the mass, m, of the student.12. What is the potential energy stored in the bungee cord just after the student steps off the bridge?
Correct, computer gets: 0 J
13. What is the mass, m, of the student?
Correct, computer gets: 4.14e+01 kg
14. What is the speed, v, of the student when the bungee cord just begins to stretch?
Correct, computer gets: 1.04e+01 m/s
15. At what height above the river does the student eventually come to rest after bobbing up and down a few times?
Explanation / Answer
12. Ug = 0
13. 0 + 0 + 0 = (-mx 9.81 x 51) + (20)(51-5.5)^2/2 + 0
m = 41.4 kg
15. that will be the equiibrium position.
at eq. position,
Fnet = k x - m g = 0
x = (41.4 x 9.81) / (20) = 20.3 m
height above river = 51 - 20.3 - 5.5 = 25.2 m ......Ans