Question

What is the acceleration of Mr. Brown if he runs with an initial velocity of 4m/s and end up running 15m/s over a distance of 20 m

Answer 1

There is a formula, I think: \[v _{2}^{2}-v _{1}^{2}=2as\]
Since we already knew \[v _{2}=15m/s\] \[v _{1}=4m/s\] \[s=20m\]
we can easily calculate the a \[a=\frac{ v _{2}^{2}-v _{1}^{2} }{ 2s }\]
which is \[a=\frac{ 15^{2}-4^{2} }{ 2\times20 }=5.225m/s ^{2}\]