|1B-4 :||Force Required to Accelerate a Rocket||4 pts|
|NASA would like a rocket to accelerate upward at a rate of 125 ft/s2. The mass of the rocket is 35,000 lbm. Determine the upward thrust force, in lbf, that the rocket engine must produce.|
|Read:||This is a direct
application of Newton's 2nd Law of Motion in the AE System of units.
The key to solving this problem is a clear understanding of gc.
|Equations / Data / Solve:|
|We begin with Newton's 2nd Law of Motion :||
|The force required to lift the rocket and accelerate it upward depends on both the weight of the rocket (and therefore the g) and the rate at which the rocket must be accelerated…120 ft/s2. Therefore:|
|We can now substitute Eqn 1 into Eqn 2 to get :|
|Now, we can plug in the values :||atotal||157.174||ft/s2|
|Note, in the absence of gravity, weightlessness, it would still require a force of Facc = 135,979 lbf to accelerate the rocket at a rate of 125 ft/s2.|