What is temperature? what instrument is used to measure temperature?

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)

Which of these is the best way to manage a natural resource

What happens to the electrostatic force between two charged particles if the distance between them is doubled?