The impact force depends on what the 10kg mass is made of and what it hits. One way to visualise this is that it will be higher for concrete than carpet because the "stopping distance" is shorter.
If you assume it hits something like modelling clay and has constant deceleration you can estimate using..
V2 = U2 +2as
where
U2 = velocity at impact
V2 = velocity after impact, probably zero
a = acceleration
s = distance (eg depth of impact crater)
So you could measure the depth of the impact crater and plug in the numbers to estimate the deceleration "a".
Then use F = ma to estimate the implied impact force.
The results will be very approximate. In the real world it's better to attach an accelerometer to the mass and measure "a".