Answer:
560 N/m
Explanation:
F = kx
75 N = k (0.61 m − L)
210 N = k (0.85 m − L)
Divide the equations:
2.8 = (0.85 − L) / (0.61 − L)
2.8 (0.61 − L) = 0.85 − L
1.708 − 2.8L = 0.85 − L
0.858 = 1.8L
L = 0.477
Plug into either equation and find k.
75 = k (0.61 − 0.477)
k = 562.5
Rounded to two significant figures, k = 560 N/m.
