2-2 tangential acceleration a is variable acceleration,
Positive pressure n = fn = m (v 2/r)
Friction is resistance.
ma=-μN=-μm(v^2/R)
A =-μ (v 2/r), that is, dv/dt =-μ (v 2/r) separates variables and integrates them.
∫ dv/v 2 = ∫ (-μ/r) dt, and the integration limit is (v0-> v), (0-> t)
Integral result: V-T relation V = v0.r/(r+μ v0.t) (1).
According to the formula (1)ds/dt = v 0. r/(r+μv 0. t), separate variables and integrate.
∫ds=∫(v0。 R/(r+μ v 0.t)) dt, and the integral limit is (0-> s), (0->; t)
Integral result: s-t relation s = v0.r.ln (r+μ v0.t/r).
2-3 When I have time.