Sanity check please -- Load cable swinging outward on a rotating crane

Click For Summary
SUMMARY

The discussion focuses on the dynamics of a rotating crane, specifically analyzing the relationship between the load cable and the radius of rotation. The equation derived is -m*(w^2)*(r1+r2)=m*g*tan(theta), which simplifies to express r1 in terms of r2 and other variables. Participants confirm the correctness of the approach while emphasizing the need to eliminate unnecessary variables, particularly the mass (m). The key takeaway is that the radius of rotation (R) is the sum of r1 and r2, and r2 should be directly proportional to the angular velocity squared (ω²).

PREREQUISITES
  • Understanding of rotational dynamics
  • Familiarity with the concepts of torque and angular velocity
  • Knowledge of trigonometric functions, specifically tangent
  • Basic algebra for manipulating equations
NEXT STEPS
  • Study the principles of rotational dynamics in mechanical systems
  • Learn about the effects of angular velocity on forces in rotating systems
  • Explore the application of trigonometric functions in engineering problems
  • Investigate methods for simplifying equations in physics
USEFUL FOR

Mechanical engineers, physics students, and professionals involved in crane operation or design will benefit from this discussion, particularly those focusing on load dynamics and rotational mechanics.

Thickmax
Messages
31
Reaction score
8
Homework Statement
Please can my work be sanity checked? I think I'm on the right lines
Relevant Equations
See below
1624914062559.png
So I know

Fcp=-m*w^2*r

So from the equation -m*w^2*r=m*g*tan(theta)

r = r1+r2

so to rewrite

-m*(w^2)*(r1+r2)=m*g*tan(theta)
So
r1+r2=(m*g*tan(theta))/-m*(w^2)

r1=((m*g*tan(theta))/-m*(w^2)) - r2

Am I doing this nearly correct?
 
Last edited by a moderator:
Physics news on Phys.org
Thickmax said:
Am I doing this nearly correct?
Yes, but one of your variables is not in the list of those allowed in the answer. Can you see a way to get rid of it?
 
  • Like
Likes   Reactions: Thickmax
Shouldn't ##r_2## be directly proportional to ##\omega^2##?
 
Lnewqban said:
Shouldn't ##r_2## be directly proportional to ##\omega^2##?
No the crane rotates around its base column, the radius of rotation is ##R=r_1+r_2## not just ##r_2##.
 
haruspex said:
Yes, but one of your variables is not in the list of those allowed in the answer. Can you see a way to get rid of it?
I can indeed! m's are overrated! Thank you for the confirmation
 
  • Like
Likes   Reactions: Delta2

Similar threads

Replies
3
Views
1K
  • · Replies 5 ·
Replies
5
Views
1K
  • · Replies 15 ·
Replies
15
Views
2K
  • · Replies 11 ·
Replies
11
Views
3K
Replies
10
Views
2K
  • · Replies 1 ·
Replies
1
Views
832
  • · Replies 1 ·
Replies
1
Views
3K
  • · Replies 2 ·
Replies
2
Views
6K
  • · Replies 9 ·
Replies
9
Views
885
  • · Replies 9 ·
Replies
9
Views
2K