Answer
3000 N/m
Work Step by Step
Find the spring constant by dividing the magnitude of applied force by the displacement. My 90-kg friend sitting on the trampoline depresses it a distance of 0.3m. The trampoline’s upward force balances his weight.
$$k=\frac{F}{x}=\frac{mg}{x}=\frac{(90kg)(9.80m/s^2)}{0.3 m}=3 \times 10^3 N/m$$
Your answer may vary.