Answer:
Option A
44 N/m
Explanation:
Work, [tex]W=0.5kx^{2}[/tex] where k is the spring constant and x is the spring extension or compression.
Making k the subject of the formula then
[tex]k=\frac {2W}{x^{2}}[/tex]
Substituting the figures given where 18 J is W and 0.9m is x then
[tex]k=\frac {2\times 18}{0.9^{2}}=44.444 N/m\approx 44 N/m[/tex]
