Answer:
4. It is the force of the road on the tires (an external force) that stops the car.
Explanation:
If there is no friction between the road and the tires, the car won't stop.
You can see this, for example, when there is ice on the road. You can still apply the brakes (internal force), but since there is no friction (external force) the car won't stop.
The force of the brakes on the wheels is not what makes the car stop, it is the friction of the road against still tires that makes it stop.
 
        
             
        
        
        
The forces that make a passenger speed up, slow down, or 
turn a curve are the same forces that have the same effect 
on the driver and anybody else in the car. 
-- Speeding up . . . 
              the back of the seat
              friction between the car seat and the seat of your pants
-- Slowing down . . . 
              the seat belt
              friction between the car seat and the seat of your pants
-- Turning away from a straight line . . .
    
              the seat belt
              friction between the car seat and the seat of your pants 
              the door, or whatever or whomever you're leaning against
        
             
        
        
        
Explanation:
see the above attachment to solve the question and get the answer. 
hope this helps you.
 
        
                    
             
        
        
        
Answer: 18.9 m
Explanation:
i did the kinematic equation & found the answer.