Answer:
40 ft/s
Explanation:
We can solve the problem by using the following SUVAT equation:
[tex]v^2-u^2 =2ad[/tex]
where
v = 0 is the final speed of the car
u = ? is the initial speed of the car
a = -4 ft/s^2 is the acceleration of the car (with a negative sign, since it is a deceleration)
d = 200 ft is the distance covered by the car
Substituting and re-arranging the equation, we find
[tex]u=\sqrt{v^2-2ad}=\sqrt{0-2(-4 ft/s^2)(200 ft)}=40 ft/s[/tex]
