Question

A cannon fires a shell with a speed of 84 m/s2 When
the cannon is inclined at 45°, the horizontal distance
covered is observed as 630 m. What is the percentage
decrease in the horizontal distance observed due to
air resistance?​

Answer 1

% decrease= diffrence in range observed and range calculated /range calculated

Range (calculated)= $u^{2}$sin2∅/g

∅=45° 2∅=90°

Range= u2/g= 84x84/10= 705.6

%decrease= 705.6-630/705.6 x100= 11% decrease