Which instrument is launched into the atmosphere to collect pressure, temperature, humidity, wind speed, and other data?
a. satellite
b. barometer
c. radiosonde
d. hygrometer

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)