Downhill project of tourist attractions: a steel cable is installed from the mountain to the foot of the mountain, and people sit in the hanging basket and slide down quickly along the steel cable at

Downhill project of tourist attractions: a steel cable is installed from the mountain to the foot of the mountain, and people sit in the hanging basket and slide down quickly along the steel cable at an inclination angle of θ through ropes and pulleys. So that the downward direction of the steel cable is taken as the positive direction of the X axis,

The vertical steel cable establishes a rectangular coordinate system downward in the positive direction of the Y axis,

As shown in the figure, the force is obtained by Newton's second law:

For pulley: Mgcosθ+N2cos(θ-α)-N 1=0? ①

Mgsinθ+N2sin(θ-α)-μN 1=Ma？ ②

For people: mgcosθ-N2cos(θ-α)=0? ③

mgsinθ-N2sin(θ-α)-kmg=ma？ ④

The solution of 1234 is: a=g(sinθ-μcosθ-kmM+m),

α=θ-arctan(μ-kM(M+m)cosθ)，

When μ = km (m+m) cos θ and μ≠0, k≠0, α = θ, a < g? sinθ。

Answer: In the stable motion state, when μ = km (m+m) cos θ and μ≠0, k≠0, α = θ, a < gsinθ.