Answer
given,
diameter of work piece = 50 mm
height = 40 mm



V = 78,739 mm³
at h = 30 mm
= 2,618 mm²


d = 57.73 mm
= 1.154
F = 1.154 × 516.67× 2618
F = 1560.92 kN
At h = 20 mm



V = 78,739 mm³
at h =20 mm
= 3936.95 mm²


d = 70.8 mm
= 1.283
F = 1.154 × 574.18× 3936.95
F = 2900 kN