We analyzed the biceps muscle example with the angle between forearm and upper arm set at $90($see figure below$).$

Find the force exerted by the biceps muscle when the angle is $140$ and the forearm is in a downward position. $($Assume that

r$1=3\mathrm{.}0$ cm$,$

r$2=14$ cm$,$

r$3=36$ cm$,$

ma $=2\mathrm{.}6$ kg$,$

and

mb $=3\mathrm{.}6$ kg$.$

Enter the magnitude.$)$

N