Question
1.
2.
An object is dropped from a tower, 181 ft above the ground. The object's height above ground t sec into the fall is s= 181 - 16t2. What is the object's velocity, speed, and acceleration at time t? About how long does it take the object to hit the ground? What is the object's velocity at the moment of impact? When a model rocket is launched, the propellant bums 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 parachute shortly after the rocket starts down. The parachute slows the rocket to keep it from breaking when it lands. The figure here shows the velocity data from the & flight of the model rocket. Use the data to complete parts (a) through (g). How fast was the rocket climbing when the engine stopped?
Explanation / Answer
ques 1
s= 181 - 16t^2
velocity = ds/dt = -32t ft/sec
acceleration = -32 ft/sec^2
when height is zero, s= 0
=> 181 = 16t^2
=> t = 3.36 sec
velocity = -32*3.36 = -107.63 ft/sec
ques 2
a) 190 ft/sec
