Question

A trench mortar fires a shell at an angle of 30° with the horizontal and with a speed of 400 m/s. Find its range and the maximum height it attains. (a)Range (b) Height

Answer 1

if you don't have the formulas handy, you can find them and their derivations in the wikipedia article on Trajectory.

Answer 2

vertical speed = 200 = Vi
m g h = (1/2) m Vi^2
solve for h = 200^2 / (2g) = max height
find time to top
v = Vi - g t
0 at top so
t = 200 / g at top
time in air = 2 t = 400/g
horizontal speed = 400 cos30 = u
range = u * 400/g