A mass that weighs 8lb stretches a spring 6in. the system is acted on by an external force of 8 sine ⁢ left-parenthesis 8 t right-parenthesis. if the mass is pulled down 3in and then released, determine the position of the mass at any time t. assume that the u-axis is directed downwards and g equals 32 ⁢ft/s2. express your answer in as a linear combination of sine ⁢ a ⁢ t ⁢ and cosine ⁢ a ⁢ t