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Static equilibrium, diving board

  • Thread starter BikeSmoth
  • Start date
  • #1
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Homework Statement


A person who weighs 620 N stands at x = 5.00 m, right on the end of a long horizontal diving board that weighs 350 N. The diving board is held up by two supports, one at its left end at x = 0, and one at the point x = 2.00 m. (a) What is the force exerted on the support at x = 0? (b) What is the force acting on the other support? (Use positive to indicate an upward force, negative for a downward force.)


Homework Equations


sum T=0, T=FR
Mgp=wieght of the person
Mgb=weight of the board
FA=force at point a - the left most support
FB=Force at point b - the rightmost support

The Attempt at a Solution


I dont know what im doing wrong, but apparently these answers are incorrect.
(a) sum T= 0 =-Mgp*Rp+(-Mgb)*Rb+FA*Ra
FA=[Mgp*Rp+Mgb*Rb]/Ra
all about point b
FA=[620N*3m+350N*.5m]/-2m
FA=-1017.5N
(b)FB=[Mgp*Rp+Mgb*Rb]/Rb
about point a
FB=[620*5+350*2.5]/2
FB=1987.5
 

Answers and Replies

  • #2
PhanthomJay
Science Advisor
Homework Helper
Gold Member
7,146
491

Homework Statement


A person who weighs 620 N stands at x = 5.00 m, right on the end of a long horizontal diving board that weighs 350 N. The diving board is held up by two supports, one at its left end at x = 0, and one at the point x = 2.00 m. (a) What is the force exerted on the support at x = 0? (b) What is the force acting on the other support? (Use positive to indicate an upward force, negative for a downward force.)


Homework Equations


sum T=0, T=FR
Mgp=wieght of the person
Mgb=weight of the board
FA=force at point a - the left most support
FB=Force at point b - the rightmost support

The Attempt at a Solution


I dont know what im doing wrong, but apparently these answers are incorrect.
(a) sum T= 0 =-Mgp*Rp+(-Mgb)*Rb+FA*Ra
FA=[Mgp*Rp+Mgb*Rb]/Ra
all about point b
FA=[620N*3m+350N*.5m]/-2m
FA=-1017.5N
(b)FB=[Mgp*Rp+Mgb*Rb]/Rb
about point a
FB=[620*5+350*2.5]/2
FB=1987.5
Your numbers are OK (might want to round them off), but read the question carefully. It asks for the force on the supports, not the force of the supports on the diving board (think of Newton 3).
 

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