Chapter 8 - Potential Energy and Conservation of Energy - Problems - Page 209: 84b

$v =5.34m/s$

The energy of the spring is transferred through kinetic energy to the object $W = K.E$ $W = \frac{1}{2}mv^2$ $\frac{2W}{m} = v^2$ $\sqrt {\frac{2W}{m}} = v$ $v =\sqrt {\frac{2W}{m}} $ $v= \sqrt {\frac{2\times31J}{2.17kg}} $ $v =5.34m/s$