f.4 physics (urgent)

As the cannon ball shoots at a speed of 400 m/s at an angle of 35°

So, the horizontal speed of the cannon ball

= 400cos35°

= 327.66 m/s

Therefore, by the law of conservation of momentum

Initial momentum = finial momentum

m1u1 + m2u2 = m1v1 + m2v2

(5)(0) + (200)(0) = (5)(357.66) + (200)v2

v2 = -8.19 m/s

So, the recoil speed of the cannon is 8.19 m/s. And the answer is C.