Step-by-step explanation:
The given data is as follows.
height (h) = 4.70 m, mass = 81.0 kg
t = 1.84 s
As formula to calculate the velocity is as follows.
= 2gh
=

= 92.12

As relation between force, time and velocity is as follows.
F =

Hence, putting the given values into the above formula as follows.
F =

=

= 4055.28 N
Thus, we can conclude that the magnitude of the average force exerted on the diver during that time is 4055.28 N.