a spring-powered dart gun is un-stretched and has a spring constant 12.0 n/m. the spring is compressed by 8.00 cm and a 5.00 gram projectile is placed in the gun. the velocity of the projectile when it is shot from the gun is: a. 1.52 m/s. b. 2.54 m/s. c. 3.92 m/s. d. 4.24 m/s. e. 5.02 m/s.