An Ideal Spring Is Used to Fire a 15

Multiple Choice

An ideal spring is used to fire a 15.0-g block horizontally. The spring has a spring constant of 20 N/m and is initially compressed by 7.0 cm. The kinetic energy of the pellet as it leaves the spring is:

A) zero
B) 2.5 * 10^-2 J
C) 4.9 * 10^-2 J
D) 9.8 * 10^-2 J
E) 1.4 J