Answer:
The answer to your question is a = 0.25 m/s²
Explanation:
Data
mass = m = 400 kg
Force = F = 100 N
acceleration = a = ? m/s²
Process
To solve this problem use Newton's second law that states that the force applied to an object is directly proportional to the mass of the body times its acceleration.
Formula
F = ma
solve for a
a = 
Substitution

Simplification and result
a = 0.25 m/s²
Gravity is the correct answer.
If the car in the opposite direction turns the signal on your vehicle, then it is only likely to give way and let him or her turn before you make your turn because he or she is in the right of way and by doing this, it will prevent any complication from happening and to be able to show respect and politeness in driving.