Which object has the most thermal energy? O A. A 6 kg rock at 15°C
O B. A 10 kg rock at 15°C
O C. A6 kg rock at 10°C
O D. A10 kg rock at 10°C
Help fast please

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)