An object is dropped from a window halfway up the empire state building (625ft.) how long will the object be i?

the object is influenced only by the gravity of earth. the equations given are: h(t)=-1/2gt^2+vt+h0 or -1/2gt^2+vt+h=0 what is the value of each variable g=? v=? and h0=? how many seconds till it hits the floor?