Answer:
12.974 m/s
Explanation:
t = Time taken
u = Initial velocity
v = Final velocity
s = Displacement
g = Acceleration due to gravity = 9.81 m/s²
[tex]\mu[/tex] = Coefficient of friction =0.66
a = Acceleration = [tex]\mu g[/tex]
[tex]v^2-u^2=2as\\\Rightarrow -u^2=2\mu gs-v^2\\\Rightarrow u=\sqrt{v^2-2\mu gs}\\\Rightarrow u=\sqrt{0^2-2\times -(9.81\times 0.66)\times 13}\\\Rightarrow u=12.974\ m/s[/tex]
Car's original speed before braking was 12.974 m/s
