Hello DBA

Welcome to Math Help Forum! I assume that is measured positive upwards, so represents the heightabovethe equilibrium position, which is 24 feet below the ceiling. (Your statement of the question says that is the distancefromthe equilibrium position, which is not the same thing!)

(a) When . On the assumption I've made above, this means that the mass is 2 feet below the equilibrium position. So the starting position of the mass is 26 feet below the ceiling.

(b) When . So the mass is feet below the ceiling at .

(c) When

the first time the mass is in the equilibrium position is after sec.

Grandad