# A projectile is thrown with a speed 𝑢 at an angle θ to the horizontal. The radius of curvature of itstrajectory when the velocity vector of the projectile makes an angle α with the horizontal is

Question : A projectile is thrown with a speed 𝑢 at an angle θ to the horizontal. The radius of curvature of its trajectory when the velocity vector of the projectile makes an angle α with the horizontal is

(A) $\dfrac{u^{2}\cos ^{2}\alpha }{g\cos ^{2}\theta }$

(B) 2 $\dfrac{u^{2}\cos ^{2}\alpha }{g\cos ^{2}\theta }$

(C) $\dfrac{u^{2}\cos ^{2}\theta }{g\cos ^{3}\alpha }$

(D) $\dfrac{u^{2}\cos ^{2}\theta }{g\cos ^{2}\alpha }$