Calculating Diving Board Forces: Mass, Distance, and Gravity Explained

[Momentum09]

Homework Statement

The diving board shown in figure has a mass of 35kg. O = 65kg diver

[1.2m] [3.9m] O
--------------------
l l
A B

A) Find the magnitude of the force on the support A when a 65kg diver stands at the end of the diving board.
B) Find the magnitude of the force on the support B.

Homework Equations

T = F x d

The Attempt at a Solution

For A), do I find the center of mass of the board and multiply that by 65kg and 9.8?
For B), is it the total distance x gravity x mass of diver?

Please correct me if I'm wrong. Thank you so much!

 

[Momentum09]

Note: The length from A to B is 1.2m, and from B to O is 3.9

 

[andrevdh]

A) You can solve for the force at A by equating the moments about B.
The force at A should be vertically downwards since the board need to be pulled down at this point in order to keep it horizontal. The force at B will be vertically upwards since the support at B need to support the weight of the diver and the board.

So in summary the moment of the force at A should be equal to the sum of the moments of the weight of the board and the moment of the weight of the diver all about point B.