A community for students.
Here's the question you clicked on:
 0 viewing
Hunus
 4 years ago
Can someone help me understand this?
Hunus
 4 years ago
Can someone help me understand this?

This Question is Closed

Hunus
 4 years ago
Best ResponseYou've already chosen the best response.0I'm reading a book on classical mechanics and I can't quite catch on to what the author is saying. The scalar product \[\vec r \cdot (d\vec r)= r(d\vec r)_r\]where \[ (d\vec r)_r\] is the projection of \[d\vec r\] on the vector \[\vec r\] This projection is equal to \[d\vec r\] the increment of the magnitude of the vector \[\vec r\] Therefore \[\vec r \cdot (d\vec r)= r*dr\]

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0dw:1335174774073:dwfrom the sketch you can see\[\vec r \cdot d\vec r= \left \vec r \right \left d\vec r \right \cos \theta\]and\[ \left d\vec r \right \cos \theta=dr\]hence:\[\vec r \cdot d\vec r= r\:dr\]

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0l dont understand the language of the author but this is a vector as you see that it have direction and magnitube. this vector have components Y&X becouse of the angle on the xaxes so l think this language is explaining that
Ask your own question
Sign UpFind more explanations on OpenStudy
Your question is ready. Sign up for free to start getting answers.
spraguer
(Moderator)
5
→ View Detailed Profile
is replying to Can someone tell me what button the professor is hitting...
23
 Teamwork 19 Teammate
 Problem Solving 19 Hero
 Engagement 19 Mad Hatter
 You have blocked this person.
 ✔ You're a fan Checking fan status...
Thanks for being so helpful in mathematics. If you are getting quality help, make sure you spread the word about OpenStudy.