View Single Post
  #4   Spotlight this post!  
Unread 31-12-2008, 18:14
ParkerF's Avatar
ParkerF ParkerF is offline
Learn it. Teach it. Spread it.
AKA: Parker Francis
FRC #0118
Team Role: Alumni
 
Join Date: Jun 2007
Rookie Year: 2007
Location: Atlanta, GA
Posts: 113
ParkerF has a reputation beyond reputeParkerF has a reputation beyond reputeParkerF has a reputation beyond reputeParkerF has a reputation beyond reputeParkerF has a reputation beyond reputeParkerF has a reputation beyond reputeParkerF has a reputation beyond reputeParkerF has a reputation beyond reputeParkerF has a reputation beyond reputeParkerF has a reputation beyond reputeParkerF has a reputation beyond repute
Re: Some physics/math help

Well, seeing as this is a great place to do so, I want to make sure I did this next problem correctly for self-assurance.

Quote:
Using the change (delta) in velocity that must be used to lower the perigee to a 60-mile altitude (This was your answer to the Shuttle math question for Lesson 1) and assuming the Orbiter's OMS engines have a combined force (thrust) of 12,000 lbs and the Shuttle has a weight of 250,000 lbs (with a full cargo bay), use the equations below to compute the length (or time) of the burn necessary in minutes.

f = ma force equals mass times acceleration and t = v/a time equals velocity divided by acceleration

Your acceleration will be in G's, where 1 G = 32 feet per second per second (this is how far an object travels due to the force of gravity in a vacuum).
Above is the second math problem. Below is the work I did myself.

f/m=a <- New formula

12,000 lbs / 250,000 lbs =a
.048 G =a
.048 G * (32 fps/s) =a <- Converting away from Gs
(1.536 fps/s) =a

t=v/a

t=304 fps / (1.536 fps/s)
t=197.916667 seconds
t=197.916667 seconds / 60 seconds <- Converting into minutes
t=3.29861111 minutes

If someone could spare their time to just check over this and let me know if I thought the problem through correctly, it would be greatly appreciated.

Thanks very much,
Parker Francis
__________________

Team 148 Alumnus - '07-'11
Team 3481 College Mentor - '12-'14
Team 118 Mentor - '17-Present
Reply With Quote