A body is projected at an angle of 30° with the horizontal and with a speed of 30 ms^-1. What is the angle with the horizontal after 1.5 s ? (g = 10 ms^-2)

The time of flight is given by
$\mathrm{T}=\frac{2\mathrm{usin}\theta }{\mathrm{g}}=\frac{2\times 30\times 1/2}{10}=3\mathrm{s}$
Thus, after 1.5 s, the body will be at the highest point. 
 So the direction of motion will be horizontal after 1.5 s, the angle with the horizontal is 0°.