thank you lnewqban for your time ,
i know these informations , i want to know if my calculations, used equations and last result are correct .
regards.
r = 2.5
l=10 cm
angle = 0 (maximum connecting rode elongation)
w = 0.5 (30 rpm)
n=10/2.5 = 4
so the acceleration is 1.5×0.5×0.5(1 + 1/4 ) = 0.4 m/s
friction force = 10*9.81*0.3 = 29.4 Newton.
Crank force is the mass of the object into acceleration.
So crank force = 10 × 0.4 = 4 Newton...