Initial velocity of the projectile, u=u‌cos‌45∘‌
∧
i
+u‌sin‌45∘‌
∧
j
Final velocity of the projectile, v=v‌cos‌45∘‌
∧
i
−v‌sin‌45∘‌
∧
j
At point B,v‌cos‌45∘=u‌cos‌45∘ and v‌sin‌45∘=u‌sin‌45∘ v=u‌cos‌45∘‌
∧
i
−u‌sin‌45∘‌
∧
j
The magnitude of change in the momentum between the points A and B |∆p|=|m(v−u)| ⇒‌‌∆p=2mu‌sin‌45∘ ⇒‌‌∆p=2×0.005×5√2×‌
1
√2
⇒‌‌∆p=5×10−2kg−m/s Hence, the value of the x is 5 .