(Solved): The 50-lb board is placed across the channel and a 100-lb girl attempts to walk across as shown in ...

The 50-lb board is placed across the channel and a 100-lb girl attempts to walk across as shown in (Figure 1). The coefficient of static friction at \( A \) and \( B \) is \( \mu_{s}=0.4 \). The length of the board is \( L=13 \mathrm{ft} \). K How far will she get from \( A \) before the board slips? Express your answer in feet to three significant figu