Answer:
The loss in mechanical energy is 668.25 J
Step-by-step explanation:
As per the question:
Mass of the base runner, m = 66 kg
Velocity of the runner, v = 4.5 m/s
Coefficient of friction,
![\mu = 0.70](https://img.qammunity.org/2020/formulas/physics/high-school/yydtc5sjgl7e4f4axs2zyyflvh2j1qdqlm.png)
Now,
The mechanical energy lost due to friction is provided by the work done in the form of the Kinetic energy of the runner:
Work done, W = Kinetic enrgy of the runner
W =
![(1)/(2)mv^(2)](https://img.qammunity.org/2020/formulas/chemistry/middle-school/gxb0mmt7jq1qwgwduy8evk7hlr6g61grz1.png)
W =
![(1)/(2)\tiems 66* (4.5)^(2) = 668.25 J](https://img.qammunity.org/2020/formulas/physics/high-school/5mkclkqk1p65pvydu16tldcu2xfosqttiv.png)
Work done must be - 668.25 J as the runner slows down.