Answer: [tex]83.65\times 10^{-27}\ kg.m/s[/tex]
Explanation:
Given
The velocities of the protons are 400 m/s and 450 m/s
Mass of the Proton is [tex]m=1.673\times 10^{-27}\ kg[/tex]
Since they travel in the opposite direction, therefore, their momentum cancels out each other.
Momentum is the product of mass and velocity
[tex]\therefore m(450-400)\\\Rightarrow 1.673\times 10^{-27}\times 50\\\Rightarrow 83.65\times 10^{-27}\ kg.m/s[/tex]
The direction of momentum is in the direction of proton having 450 m/s velocity.