Does anyone understand this physics challenge question?

Use the kinematics equation: vf^2=vi^2+2*a*d vi=0, solve for vf When he hits the water his velocity will be. vf=sqrt(2*9.81*4) vf=8.859 m/s Now use this equation vf=vi+a*t this time vi=8.859 m/s and vf=0 slve for a a=-vi/t 8.859/.77=11.505 m/s^2 Force equals mass time acceleration F=ma F=97*11.505 The force is 1.116 kN

This is impossible to answer, unless you make the stupid and completely wrong assumption that the water exerts a constant force. Time to reach water is sqrt(2x4/9.8) = 0.9 sec Resultant force on man while falling through the air = 97 x 9.8 = 950N downwards Resultand force to stop the man in 0.77 sec (assuming it is constant ) = 950 x .9/.77 = 1110N upwards So upwards force exerted by water = 1110 + 950 = 2060N

I answered this question just now...stop posting it! In my answer, I assumed g to be 10 (instead of 9.8 which is its actual value)! That is the reason why my answer had an uncertanity of +/- 10!

This is impossible to answer, unless you make the stupid and completely wrong assumption that the water exerts a constant force. Time to reach water is sqrt(2x4/9.8) = 0.9 sec Resultant force on man while falling through the air = 97 x 9.8 = 950N downwards Resultand force to stop the man in 0.77 sec (assuming it is constant ) = 950 x .9/.77 = 1110N upwards So upwards force exerted by water = 1110 + 950 = 2060N

I answered this question just now...stop posting it! In my answer, I assumed g to be 10 (instead of 9.8 which is its actual value)! That is the reason why my answer had an uncertanity of +/- 10!