(a) State two objects each used in sports and warfare which may be considered as projectiles. 

(b) the horizontal range R, of a projectile is given by the expression;

R = \(\frac{u^2 sin 2\theta}{g}\) where \(\theta\) is the angle of projection, g the acceleration of free fall due to gravity and u the initial velocity. At what value of \(\theta\) will R be maximium?