According to the definition of power, a powerful person is able to do which of the following?
a. lift heavy objects
b. do less work in more time
c. do more work in less time
d. exert a larger force for a longer time

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)