Solve
-The Number of Centimeters $d$ , That a Spring Is Compressed from Its Natural, Uncompressed

Multiple Choice

Solve.
-The number of centimeters, $d$ , that a spring is compressed from its natural, uncompressed position is given by the formula $d = \sqrt { \frac { 2 W } { k } }$ , where $W$ is the number of joules of work done to move the spring and $\mathrm { k }$ is the spring constant. If a spring has a spring constant of $0.2$ , find the amount of work needed to move the spring 7 centimeters.

A) $4.9$ joules
B) 49 joules
C) $9.8$ joules
D) $0.7$ joules