Answer:
Ek = 1705.28 [J]
Step-by-step explanation:
In order to solve this problem, we must remember that kinetic energy can be calculated by means of the following equation.

where:
m = mass [kg]
v = velocity [m/s]
Ek = kinetic energy [J] (Units of Joules)
For the person running
![E_(k) =(1)/(2)*52.2*(3.5)^(2) \\ E_(k) =319.72[J]](https://img.qammunity.org/2021/formulas/physics/high-school/x9gjbrq1uvxct3qpcrimd14k0cydp36ci1.png)
For the bullet

![E_(k) =(1)/(2) *0.02*(450)^(2) \\E_(k)=2025 [J]](https://img.qammunity.org/2021/formulas/physics/high-school/z2gto176n76tq6g7fxe6nngjynniaoxlx8.png)
The difference in Kinetic energy is equal to:
Ek = 2025 - 319.72
Ek = 1705.28 [J]