The question does not ask for anything in particular. I will calculate the acceleration and distance.
Answer:
The acceleration of the car is [tex]-7\ m/s^2[/tex]
The distance traveled before stopping is 350 m
Explanation:
Constant Acceleration Motion
It's a type of motion in which the velocity of an object changes by an equal amount in every equal period of time.
Being a the constant acceleration, vo the initial speed, vf the final speed, and t the time, the following relation applies:
[tex]v_f=v_o+at\qquad [1][/tex]
The distance traveled by the object is given by:
[tex]\displaystyle x=v_o.t+\frac{a.t^2}{2}\qquad [2][/tex]
The car has an initial speed of v0=70 m/s when the driver sees a cow in the road and steps on the brakes with an (assumed) constant acceleration during t=10 seconds before stopping (vf=0).
With the information provided, we can calculate the value of the acceleration and the distance traveled.
Using the equation [1] we can solve for a:
[tex]\displaystyle a=\frac{v_f-v_o}{t}[/tex]
Substituting the numerical values:
[tex]\displaystyle a=\frac{0-70}{10}=-7\ m/s^2[/tex]
The acceleration of the car is [tex]-7\ m/s^2[/tex]
The distance is now calculated by using [2]
[tex]\displaystyle x=70\cdot 10+\frac{(-7)\cdot 10^2}{2}[/tex]
[tex]\displaystyle x=700-\frac{700}{2}=350\ m[/tex]
The distance traveled before stopping is 350 m
