Answer
The max force the bicep muscle exerts on the forearm is about 1800N
Work Step by Step
We sum the torques about the elbow to solve for the force that the bicep muscle exerts on the forearm. Therefore;
$(+ \circlearrowleft) \sum \tau=0$
$\sin105^{\circ}*F*.05m-2.0kg*9.8m/s^2*.15m-25kg*9.8m/s^2*.35m=0$
$F=(2.0kg*9.8m/s^2*.15m+25kg*9.8m/s^2*.35m)/(\sin105^{\circ}*0.05m)$
$F\approx1800N$
The max force the bicep muscle exerts on the forearm is about 1800N.