When a model rocket is launched, the propellant burns for a few seconds, accelerating the rocket upward. After burnout, the rocket coasts upward for a while and then begins to fall. A small explosive charge pops out a 2007 parachute shortly after the rocket starts down. The parachute slows the rocket to keep it from breaking when it 150- lands. The figure here shows the velocity data from the flight of the model rocket. Use the data to complete parts (a) through (9). 100 velocity (ft/sec) 50 0- -50 -1004 O- 10 12 Time after launch (sec) (a) How fast was the rocket climbing when the engine stopped? ft/sec (Round to the nearest integer as needed.)