Which therapy is associated with light, but not sound?
a breaking down kidney stones
b acoustically targeting the delivery of a drug
c cauterizing an incision or wound
d ablating tumors

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)