Suppose a 32-pound weight stretches a spring 2 feet. If the weight is released from rest at the equilibrium position, find the equation of motion x(t) if an impressed force f(t) = 20t acts on the...

Suppose a 32-pound weight stretches a spring 2 feet. If the weight is released from rest at the equilibrium position, find the equation of motion x(t) if an impressed force f(t) = 20t acts on the system for 0 ≤ t < 5="" and="" is="" then="" removed="" (see="" example="" 5).="" ignore="" any="" damping="" forces.="" use="" a="" graphing="" utility="" to="" graph="" x(t)="" on="" the="" interval="" [0,="">