Answer
(a) $45N$
(b) less than
Work Step by Step
(a) We can find the required force as
$F=KL$
we plug in the known values to obtain:
$F=(250)(0.18)$
$F=45N$
(b) We know that
$F=K(\frac{1}{2}L)$
We plug in the known values to obtain:
$F=(250)(\frac{1}{2}(0.18))$
$F=22.5N$
Thus, the magnitude of the force required to compress the spring to half of its length is less than that found in part(a).
