#### Answer

The spring constant is 360 N/m

#### Work Step by Step

When the book is placed on the spring, the spring is compressed by 6 cm. The force that the spring pushes is equal to the weight of the book. Therefore;
$kx = mg$
$k = \frac{mg}{x}$
$k = \frac{(2.2~kg)(9.80~m/s^2)}{0.060~m}$
$k = 360~N/m$
The spring constant is 360 N/m.