Answer
$18.7^\circ$
Work Step by Step
1. Given $F=16.0\ lb, W=50.0\ lb$, assume the incline angle is $t$ as shown in the figure.
2. Since the forces are balanced along the incline, we have $F=W\ sin(t)$ or $50\ sin(t)=16$
3. Solve for angle $t$ to get $t=asin(\frac{16}{50})\approx18.7^\circ$
