## Engineering Mechanics: Statics & Dynamics (14th Edition)

$I_c=6.55\times 10^{-3}N\cdot s$ $I_u=6.05\times 10^{-3}N\cdot s$
The impulse for CONFOR foam can be determined as $I_c=\int Fdt$ We plug in the known values to obtain: $I_c=[\frac{1}{2}(2)(0.5)+\frac{1}{2}(0.5+0.8)(7-2)+\frac{1}{2}(0.8)(14-7)]\times 10^{-3}$ $\implies I_c=6.55\times 10^{-3}N\cdot s$ Now the impulse for Urethane foam can be calculated as $I_u=\int Fdt$ We plug in the known values to obtain: $I_u=[\frac{1}{2}(4)(0.3)+\frac{1}{2}(1.2+0.3)(7-4)+\frac{1}{2}(1.2+0.4)(10-7)+\frac{1}{2}(14-10)(0.4)]\times 10^{-3}$ $\implies I_u=6.05\times 10^{-3}N\cdot s$