Given the relationships,
[tex]h=0.4m\\m=61kg\\t=0.082s[/tex]
Given the energy conservation equation,
[tex]\frac{1}{2}mv^2 = mgh[/tex]
[tex]v= \sqrt{2gh}[/tex]
[tex]v= \sqrt{2*9.8*0.4}[/tex]
[tex]v=2.8m/s[/tex]
Since this is the initial speed and according to the problem, the final is zero,
\vec{J}=m(\vec{v}_f-\vec{v}_i)
[tex]\vec{J}=61*(0-(-2.8))[/tex]
[tex]\vec{J}=170Kg-m/s[/tex]
B) The average force would be given by the change that exists at the time during the change of time,
[tex]|F|=\frac{P_f-P_i}{\Delta t}[/tex]
[tex]|F|= \frac{m(0-v_i)}{\Delta t}[/tex]
[tex]|F| = \frac{170}{0.082}[/tex]
[tex]|F|= 2073.1N[/tex]