Joke Collection Website - Cold jokes - The radius of the vertically placed smooth iron ring is R=20cm, and there is a perforated ball M on the ring, which can only slide along the ring without friction.

The radius of the vertically placed smooth iron ring is R=20cm, and there is a perforated ball M on the ring, which can only slide along the ring without friction.

N*cosθ = m*g

N*sinθ = m*R*sinθ*ω^2

At the same time in two forms.

cosθ= g/(r*ω^2)= 10/(0.20* 10^2)= 0.5

θ = 60

In fact, a special angle θ = 0 also meets the requirements.