#### kingwinner

**Registered Senior Member**

**1) A balloon is ascending at 9.0m/s and has reached a height of 80m above the ground when it releases a package. How long does the package take to reach the ground?**

There is only one question I'd like to ask. Would the initial velocity of the dropped package be 0m/s since it is dropped?

**2) A rocket-driven sled running on a straight, level track can attain a velocity of 1600km/h in 1.8s, starting from rest. Under the last 2.00km of the track there is a trough of water. The "brakes" of the rocket consist of a scoop that displaces water from the trough, stopping the sled. Assuming that the sled stops at the end of the trough, what is the deceleration of the sled, expressed in terms of g? (g=9.8m/s^2)**

I don't know how to do question 2. Can someone give me some hints? Thank you!