Case 1 : Free Falling Masss

Input Data
m = 20 kgs
H = 0.3 M
S = 0.025 M (Excepted Stroke)
X = 300 Strokes per hour

Formuale
Ek = m x g x H = 20 x 9.8 x 0.3 = 58.8 NM
Ep = m x g x S = 20 x 9.8 x 0.025 = 4.0 NM
Et = Ek + Ep = 58.8 + 4.9 = 63.7 NM

Et/Hr = Et x X = 63.7 x 300 = 19110 Me = 2 x Et / (2 x g x H)^0.5
= 2 x 63.7 / (2 x 9.8 x 0.3)
= 21

So we search a shock absorber whose energy capacity is greater than 63.7 NM and Energy capacity per hour is greater than 19110 and Efective mass is near 20 kgs.
You can refer to the catlogue of shock absorber available with you to compare the shock absorber or oreder one from adonitech@gmail.com

Applications : Helmet test rigs, free fall drop test, paradropping, elevators.