A(n) is a thick accumulation of sediments and small tectonic blocks formed of material scraped off subducting oceanic lithosphere at a convergent margin.
a) mass movement complex.
b) continental shelf, terrain complex.
c) accretionary-wedge complex.
d) subterranean-accumulation complex.

Ahot-air balloon takes off from the ground traveling vertically with a constant upward acceleration of magnitude g/4. after time interval δt, a crew member releases a ballast sandbag from the basket attached to the balloon. how many seconds does it take the sandbag to reach the ground? (express your answer in terms of δt)