Why does hand-spinning a small mass in a vertical circular motion produces different period if the same mass is spun in a horizontal circular motion given that the radius, slotted mass are kept the same?
I did the following 2 experiments and collected their period with the same150g slotted mass, 1m radius. where I hand spin a mass (red) that is attached to the same string with the slotted mass at the other end. I spin the mass by grabbing the hollow tube (blue). Same applies to horizontal.
Now the period that I collected is $0.8s$ for horizontal circular motion and $0.7s$ for vertical circular motion. So my question is why do they produce a different or similar period? Is there a mathematical reason to explain why this happens? What are the reasons/physics concepts behind the different period?