What is the distribution of forces on a swimming pool springboard?

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Homework Help Overview

The problem involves analyzing the forces acting on a swimming pool springboard, which is supported at two points and has a boy standing at one end. The discussion focuses on the directions and magnitudes of the forces at the hinges and roller supports.

Discussion Character

  • Conceptual clarification, Mathematical reasoning, Assumption checking

Approaches and Questions Raised

  • The original poster attempts to set up equations based on the forces and torques acting on the springboard, but expresses confusion regarding the calculated force at point B. Participants question the inclusion of the reaction force RA in the torque equation and its relevance to the moment calculations.

Discussion Status

Participants are actively engaging in clarifying the roles of different forces and torques in the problem. There is a focus on understanding the correct application of torque equations, with some guidance being offered regarding the nature of forces versus torques.

Contextual Notes

The discussion is constrained by the absence of a diagram, which may limit the clarity of the forces and moments being analyzed. The original poster's calculations are also noted to be problematic, leading to further questioning of assumptions made in the setup.

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Homework Statement



The diagram (not included) shows a straight, horizontal swimming bath spring board of length 4m and weight 300N. It is freely hinged at A and rests on a roller at B where AB=1.6m. A boy of weight 400N standard at end C.
a) show directions of forces acting on A and B
b) calculate magnitudes of forces at A and at B

Homework Equations



A______________B______________C
AB= 1.6m
BC= 2.4m
AC= 4m

The Attempt at a Solution


Weight of board put at centre point (0.4m from B and 2m from C)
RA assigned as reaction force at A
RB assigned as reaction force at B

RA = 700-RB

RA+RB = 700N
(300x2)+(4x400)=RA+(RBx1.6)
2200=RA+(RBx1.6)
2200=700-RB+(RBx1.6)
1500=0.6RB
2500=RB

This figure for RB simply cannot be right and therefore really isn't helping me!
 
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(300x2)+(4x400)=RA+(RBx1.6) ---> this is the equation for the torques with respect to A. Why did you include the force RA?

ehild
 
I assumed RA was required for the anticlockwise moment? is it not?
 
RA is force, not torque. What is the torque of RA with respect to A? ehild
 

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