Astronauts in space cannot weigh themselves by standing on a bathroom scale. Instead, they determine their mass by oscillating on a large spring. Suppose an astronaut attaches one end of a large spring to her belt and the other end to a hook on the wall of the space capsule. A fellow astronaut then pulls her away from the wall and releases her. The spring's length as a function of time is shown in the figure .
What is her mass if the spring constant is 240 ?
What is her speed when the spring's length is 1.2 ?
image is http://session.masteringphysics.com/problemAsset/1001073/9/knight_Figure_14_36.jpg
The Attempt at a Solution
i got that the answer to the first question is 54.7kg
i just don't know how to find her velocity at that length
if someone can please help me