Answer:
The particle will continue moving at constant velocity
Explanation:
When the particle encounters the second force of 10 N, the net force acting on the particle becomes zero, because the two forces are equal in magnitude but opposite in direction:
[tex]F_{net}=10 N-10 N=0[/tex]
For Newton's second Law, the acceleration of the particle is proportional to the net force acting on it:
[tex]F_{net}=ma[/tex]
Therefore, since [tex]F_{net}=0[/tex], the acceleration is zero (a=0) and so the particle will keep a constant velocity.