(i) To find when the particle is at rest, set \(v = 0\):
\(-0.01t^3 + 0.22t^2 - 0.4t = 0\)
Factor out \(t\):
\(t(-0.01t^2 + 0.22t - 0.4) = 0\)
Solving \(-0.01(t^2 - 22t + 40) = 0\) gives:
\(t^2 - 22t + 40 = 0\)
\((t - 20)(t - 2) = 0\)
Thus, \(t = 2\) or \(t = 20\).
(ii) Acceleration \(a\) is the derivative of velocity:
\(a = \frac{dv}{dt} = -0.03t^2 + 0.44t - 0.4\)
To find when acceleration is greatest, differentiate \(a\) and set to zero:
\(\frac{da}{dt} = -0.06t + 0.44 = 0\)
\(t = \frac{0.44}{0.06} = 7.33\)
(iii) To find the distance, integrate velocity from \(t = 2\) to \(t = 20\):
\(s(t) = \int (-0.01t^3 + 0.22t^2 - 0.4t) \, dt\)
\(s(t) = -\frac{0.01}{4}t^4 + \frac{0.22}{3}t^3 - 0.2t^2 + C\)
Evaluate from \(t = 2\) to \(t = 20\):
\(s(20) - s(2) = \frac{2673}{25} = 106.92\)
\(Distance = 107 m (rounded to nearest whole number).\)