Need help determining F and n in terms of variables

  • Thread starter Thread starter blazeuofa
  • Start date Start date
  • Tags Tags
    Terms Variables
Click For Summary

Homework Help Overview

The problem involves determining the force (F) required to hold a box of mass (m) against a frictionless wall at an angle (θ), as well as the normal force (n) acting on the box. The context is rooted in mechanics, specifically in analyzing forces in equilibrium.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • Participants discuss the need to resolve the applied force into horizontal and vertical components to achieve equilibrium. There are questions about the correct relationships involving trigonometric functions, particularly sine and cosine, and how they relate to the forces acting on the box.

Discussion Status

The discussion is ongoing, with participants exploring different interpretations of how to resolve the forces. Some guidance has been offered regarding the necessity of including trigonometric functions in the equations, but there is no explicit consensus on the final expressions for F and n.

Contextual Notes

Participants note that the problem constraints limit the variables to m, θ, and g, which may affect the approach to finding F and n. There is also a hint that the angle θ is defined with respect to the rightward axis, which influences the direction of the force components.

blazeuofa
Messages
14
Reaction score
0

Homework Statement


A box of mass (m) is held against a frictionless wall by a force of magnitude F at an angle [tex]\theta[/tex] (above right). Determine F in terms of whatever variables are necessary. Similarly, determine the magnitude of the normal force (n) in terms of whatever variables are necessary. (Hint: you can only have m, [tex]\theta[/tex], and g in your answers)


Homework Equations





The Attempt at a Solution


F=ma, a=g
F=mg


n=F?
 
Physics news on Phys.org
They want you to resolve the Force into the horizontal and vertical components of force necessary to hold the box with no net force.

If you don't have a sinθ or cosθ in your answer you can be certain it isn't correct.
 
LowlyPion said:
They want you to resolve the Force into the horizontal and vertical components of force necessary to hold the box with no net force.

If you don't have a sinθ or cosθ in your answer you can be certain it isn't correct.

so Fx=Sin[tex]\theta[/tex] and Fy=mg

I know the answer is F=mg/sin [tex]\theta[/tex], but I thought you divide Fx by Fy? So why is the answer F=mg/sin [tex]\theta[/tex]?
 
Not quite, because they defined the angle θ with respect to "rightward" axis. Hence the component that balances the m*g is going to be the vertical sinθ component.
 

Similar threads

  • · Replies 41 ·
2
Replies
41
Views
4K
Replies
5
Views
2K
  • · Replies 8 ·
Replies
8
Views
1K
  • · Replies 3 ·
Replies
3
Views
2K
Replies
13
Views
3K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 9 ·
Replies
9
Views
2K
  • · Replies 21 ·
Replies
21
Views
2K
Replies
6
Views
4K
Replies
17
Views
3K