f？ lsin37 -mg？ 12(l-lcos 37)-mg(l-lcos 37)= 12？ mvA2+ 12m(2vA)2

The solution is vA=6gl5.

When the speed reaches the maximum for the first time, the resultant torque is zero. According to the torque balance conditions, there are

Mg? 12lsinθ+mg？ lsinθ=F？ lcosθ

Solution: θ = 45.

So, the answer is: 6gl5；; 45