Question

HELP!!
A bungee cord is attached to a wagon and is used to pull a child while you take her for a ride. The bungee's original unstretched length is 1.3 m. The
girl weighs 220 N, and the wagon weighs 75 N. You accelerate from rest to your normal walking speed of 1.5 m/s in 2 seconds, and you notice that
while you are accelerating, the bungee's length increases to about 2 m. What is the force constant of the bungee cord, assuming it obeys Hooke's
law?
45 N/m
55 N/m
32 N/m

Answer 1

Answer:

32 N/m

Explanation:

∑F = ma

kx = ma

k (2 m − 1.3 m) = ((220 N + 75 N) / 9.8 m/s²) ((1.5 m/s − 0 m/s) / 2 s)

k × 0.7 m = 30.1 kg × 0.75 m/s²

k = 32 N/m