• #1
haruspex
Science Advisor
Homework Helper
Insights Author
Gold Member
2020 Award
36,929
7,193
Corrections to
MIT Open Courseware 8-01sc classical mechanics,
fall 2016
Applying Newton’s Laws to systems of Varying Mass
PDF Course Link
My concerns with the solutions provided on the cited MIT Open Courseware web page are, mostly:


Despite arriving at the correct answers, the algebraic methods are invalid. As a result, they can be utterly confusing to the student.
The main flaw, repeated throughout, is writing a system state (momentum) as a function of time only, but effectively defining it as a function of two variables. In places, this leads to equations that are clearly contradictory.


This mangled treatment likely results from an attempt to use ##F=\frac {dp}{dt}## in conjunction with ##\frac{dp}{dt}=m\frac{dv}{dt}+\frac{dm}{dt}v##, instead of the deprecated ##F=ma##. As we shall see, although the ‘more fundamental’ momentum change formula can be...

Continue reading...
 
  • Like
Likes bhobba, Delta2, Greg Bernhardt and 1 other person

Answers and Replies

  • #2
711
273
That's a bit concerning. I usually take material from MIT as being pretty much 'gospel' !
 
  • Like
  • Sad
Likes bhobba and Delta2

Related Threads on Corrections to MIT Open Courseware: Systems of Varying Mass

Replies
3
Views
2K
Replies
7
Views
2K
  • Last Post
Replies
7
Views
2K
  • Last Post
2
Replies
42
Views
11K
  • Last Post
Replies
5
Views
2K
Replies
1
Views
2K
  • Last Post
Replies
4
Views
2K
  • Last Post
Replies
8
Views
7K
  • Last Post
Replies
12
Views
3K
  • Last Post
Replies
4
Views
1K
Top