A 0.5kg mass is attached to a horizontal spring of force constant 100N m−1. The spring is compressed by 0.10m and released from rest on a smooth horizontal surface. Calculate the speed of the mass as it passes through the natural (unstretched) length of the spring.
a) 2.0m s−1
b) 0.71m s−1
c) 1.4m s−1
d) 1.0m s−1