What types of energy can be present when using a cell phone? Heat, magnetic, light, sound, gravitational, chemical, electrical, elastic, nuclear, and solar. Choose all that apply

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)