Calculate $($a$)$ the impulse experienced when a $70$

kg person lands on firm ground after jumping from a height

of $3\mathrm{.}0$ m and $($b$)$ Estimate the average force exerted on the

person$$s feet by the ground if the landing is stiffed leg $($c$)$

with bend legs. $($With stiff legs, assume the body moves $1\mathrm{.}0$

cm during impact and when the legs are bent about $50$ cm$)$