If a head on automobile collision,a person momentum could be reduced from 2000kgm/s to zero in just 0.1s . If this occurs the average force exerted to stop the person is

1.200 N
2.2000 N
3. 20,000 N
4. can't answer without knowing the person name.
Here is my answer 200*0.1s equals to 200N am I'm right

Not quite right. From principles of impulse and momentumm:


F \Delta t = m \Delta v


Here you have t = 0.1s and m \Delta v = 200 Kg m/s. Solve for F.