Answer:
1373.4 N/m
Explanation:
Hooke's law states that the extension of a spring and force are related by the expression, F=kx where k is spring constant, x is extension of spring and F is the applied force. Making k the subject of the formula then
[tex]k=\frac {F}{x}[/tex]
Also, F=gm hence the above formula is modified as
[tex]k=\frac {gm}{x}[/tex]
Taking g as 9.81 m/s2 , x as 0.5 m and m as 70 kg then
[tex]k=\frac {9.81\times 70 kg}{0.5m}=1373.4 N/m[/tex]