A Spring with A $3 - \mathrm { kg }$ Mass Is Held Stretched

Short Answer

A spring with a $3 - \mathrm { kg }$ mass is held stretched $0.9 \mathrm {~m}$ beyond its natural length by a force of $30 \mathrm {~N}$ . If the spring begins at its equilibrium position but a push gives it an initial velocity of $1 \mathrm {~m} / \mathrm { s }$ , find the position $x ( t )$ of the mass after $t$ seconds.