Answer:
40 N/m
Step-by-step explanation:
Assuming that the missing diagram is as attached, then we can deduce from Hooke's law that the extension of a spring is directly proportional to the applied force. This is mathematically expressed as
F=kx
Here, F represent the applied force, x denote the extension of the spring while k is the spring constant.
From the attached diagram, extension of the spring x=1-0.5=0.5m
Substituting 20 N for F and 0.5 m for x then
20=0.5k
k=20/0.5=40 N/m