A diving board `3.00 m` long is supported at a point `1.00 m` from the end and a diver weighing `500 N` stands at the free end. The diving board is of uniform cross section and weighs `280 N`. Find.
The force at the end that is held down.

Options

A. `780N`
B. `220N`
C. `1920N`
D. `1140N`

Answer

D

Explanation

Take torques about the left end of the board inward

The force `F` at the support point is found from
`F(1.00m)=+(280N)(1.50m)+(500N)(3.00m)`
`implies F=1920N`
The net force must be zero so the force at the left end is
`(1920N)-(500N)-(280N)=1140N,` downward