## Question:

From experiments, the time variation of the vertical force on a runner’s foot as he strikes and pushes off the ground is shown in the graph.These results are reported for a 1-lb static load, i.e., in terms of unit weight. If a runner has weight W, determine the approximate vertical impulse he exerts on the ground if the impulse occurs in time ${ t }_{ 5 }$. Units Used: ms = ${ 10 }^{ −3 }$ s Given: W = 175 lb , ${ t }_{ 1 }$ = 25 ms , t = 210 ms , ${ t }_{ 2 }$ = 50 ms , ${ t }_{ 3 }$ = 125 ms , ${ t }_{ 4 }$ = 200 ms , ${ t }_{ 5 }$ = 210 ms , ${ F }_{ 2 }$ = 3.0 lb , ${ F }_{ 1 }$ = 1.5 lb