Homework Help: Static Equilibrium of Board

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1. Apr 11, 2016

STEM_STRUGGLES

1. The problem statement, all variables and given/known data
There is a diving board held up by two pillars A and B, and there is a diver standing on it's edge. What are the directions of the forces exerted at points A and B? Picture Below:

2. Relevant equations
F_NET = 0
T_NET =0

3. The attempt at a solution
I thought both A and B were pointed upwards since the diver is pushing downwards, but apparently B is upwards and A is downwards.

2. Apr 11, 2016

Staff: Mentor

Welcome to the PF.

Think of a see-saw with the point B being the fulcrum. What do you see now?

3. Apr 11, 2016

STEM_STRUGGLES

Oh, wow! I see point B as pointing up now, but what about point A? If I use A as the fulcrum, doesn't that still make it point upwards in order to keep the board from rotating downwards?

4. Apr 11, 2016

Staff: Mentor

B is the fulcrum. Did you never use a see-saw?

5. Apr 11, 2016

STEM_STRUGGLES

Ok, I'm still confused. Sorry. If B is the fulcrum and it's force is going upwards, I'm still not understanding how A's force is going downwards. Given the see-saw example, the diver is on one end pulling down on the end of the see-saw, and A is somehow pulling downwards even though it's on the bottom? I really appreciate the help!

6. Apr 11, 2016

Staff: Mentor

What if the person sitting on the right side of the see-saw is heavier than the person sitting on the left side? What happens to the left side of the see-saw?

7. Apr 11, 2016

STEM_STRUGGLES

It goes upwards, but I don't know what happens at point A because A is on the underside of the diving board.

8. Apr 12, 2016

haruspex

Imagine taking pillar A away. Which way would the part of the board above A move?
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