• Support PF! Buy your school textbooks, materials and every day products Here!

Statics (force projections)

  • Thread starter pearss
  • Start date
  • #1
8
0

Homework Statement


I have a force in three dimensions such that:
F=600N
Alpha(angle with x axis) = 120
Beta(angle with y axis) = 60
Omega(angle with z axis) = 45

I'm to find the projection of F along the y axis.

The Attempt at a Solution



I found the force vector for this force by

F=F(cos120i+cos60j+cos45k)
F=600N(-.5i+.5j+.707k)
F= -300i+300j+424.2k

now i know to use a dot product between the force vector and the unit vector of the vector that i'm trying to find a projection onto....but since the vector is the y axis i'm unsure about what to do from here.

I thought that u_OY = oy/magnitude oy

0i+j+0k / 1 = j

and a dot product between this and my force vector would just give me the y component of that force vector....300.

but i'm pretty sure this is wrong. does anybody have any hints? Thanks much
 

Answers and Replies

  • #2
nvn
Science Advisor
Homework Helper
2,128
32
pearss: Your answer is correct. Nice work.
 
  • #3
8
0
Thanks for the comfirmation nvn
 

Related Threads on Statics (force projections)

  • Last Post
Replies
9
Views
931
  • Last Post
Replies
3
Views
2K
  • Last Post
Replies
2
Views
12K
  • Last Post
Replies
4
Views
1K
Replies
1
Views
3K
  • Last Post
Replies
2
Views
4K
  • Last Post
Replies
1
Views
1K
  • Last Post
Replies
3
Views
626
Replies
4
Views
18K
Replies
1
Views
1K
Top