Is the problem wrong (deals with resolving vectors into their components)?

  • #1

Homework Statement


4.9b cites the y components to be sin degree and 4.9a is somehow cos degree for the x components (see picture)
physics.png


Homework Equations


Here's a different textbook that supports my claim (see picture)

physics1.png


The Attempt at a Solution


Shouldn't the y components for problem 4.9b be cos instead of sin based on how the angle of the vector is oriented? Isn't this vice versa for problem 4.9a (this should be sin)
 

Answers and Replies

  • #2
172
2
When splitting a vector V, the y component is V*sinθ, and the x component is V*cosθ. It doesn't matter how the vector is oriented. The picture you posted from another textbook confirms what it shows in the first picture. If you rearrange the sin equation, you get V*sinθ=Vy (which is the y component of vector V)
 
  • #3
I just realized that T1 stood for vector V
I thought that T1 somehow was identifying Vector y

I feel stupid...REALLY stupid...
 
  • #4
172
2
Don't worry about it, I think physics makes everybody feel stupid. I'd like to point you to a quote by a great physicist, Richard Feynman.

http://youtu.be/lytxafTXg6c
"When you are thinking about something that you don’t understand you have a terrible, uncomfortable feeling called ‘confusion’. It’s a very difficult and unhappy business. So, most of the time you are rather unhappy, actually, with this confusion. You can’t penetrate this thing. Now, is the confusion… is it because we are all some kind of apes that are kind of stupid working against this? Trying to figure out to put the two sticks together to reach the banana and we can’t quite make it? …the idea ? And I get that feeling all the time: that I am an ape trying to put two sticks together. So I always feel stupid. Once in a while, though, everything — the sticks — go together on me and I reach the banana.”
 
  • Like
Likes 1 person
  • #5
Thanks!
 

Related Threads on Is the problem wrong (deals with resolving vectors into their components)?

Replies
4
Views
968
Replies
4
Views
796
  • Last Post
Replies
15
Views
1K
Replies
7
Views
9K
  • Last Post
Replies
1
Views
585
Replies
2
Views
1K
  • Last Post
Replies
1
Views
1K
  • Last Post
Replies
2
Views
1K
  • Last Post
Replies
2
Views
1K
Replies
2
Views
5K
Top