A Spring with a 3-Kg Mass Is Held Stretched 0 $$1$$

Multiple Choice

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

A) $x ( t ) = 1 \sin ( 7 t )$
B) $x ( t ) = 0.3 \sin \left( \frac { 10 } { 3 } t \right) + 0.4 \cos \left( \frac { 10 } { 3 } t \right)$
C) $x ( t ) = 0.3 \sin \left( \frac { 10 } { 3 } t \right)$
D) $x ( t ) = 0.4 \cos \left( \frac { 10 } { 3 } t \right)$
E) $x ( t ) = \frac { 10 } { 3 } \sin ( 7 t )$