Can I get some Physics help?

forearm/

Actually, the torque depends on the angle that the forearm makes with horizontal, since the torque produced by the ball depends in part on the torque that the weight produces about the elbow. I guess we have to ignore this fact and consider only that

torque τ = I*α

Treating the ball as a point particle,

I = mr² = 2.8kg * (0.31m)² = 0.269 kg·m²

and

α = a / r = 5.2m/s² / 0.31m = 16.8 rad/s²

and so

τ = 4.5 N·m

then

F = τ / 0.025 = 180 N

sphere/

If the sphere is solid, I = (2/5)mr² = 1.94 kg·m²

But if the sphere is hollow, then I = (2/3)mr².

Hope this helps!

F = m*a = 2.8kg*5.1m/s² = 14.28N

Balancing torques about the pivot:

14.28•0.31 = 4.4268 = Ft•0.025

Ft = 4.4268/0.025 = 177N <<<