Answer:
25.71486 seconds
Explanation:
t = Time taken
u = Initial velocity = 60 mph
v = Final velocity = 80 mph
s = Displacement = 0.5 mile
a = Acceleration
Converting to m/s
[tex]60\times \dfrac{1609.34}{3600}=26.8223\ m/s[/tex]
[tex]80\times \dfrac{1609.34}{3600}=35.7631\ m/s[/tex]
From equation of motion
[tex]v^2-u^2=2as\\\Rightarrow a=\dfrac{v^2-u^2}{2s}\\\Rightarrow a=\dfrac{35.7631^2-26.8223^2}{2\times \dfrac{1609.34}{2}}\\\Rightarrow a=0.34769\ m/s^2[/tex]
[tex]v=u+at\\\Rightarrow t=\dfrac{v-u}{a}\\\Rightarrow t=\dfrac{35.7631-26.8223}{0.34769}\\\Rightarrow t=25.71486\ s[/tex]
Time taken is 25.71486 seconds