Kinematics - Finding the Equation of Displacement from Velocity

Kinematics - Finding the Equation of Displacement from Velocity

TGM Original Questions

A particle \(P\) moves in a straight line such that \(t\) seconds after starting at displacement \(+1\) metre from \(O\), its velocity, \(v\) m/s, is given by \(v = \frac{t^4}{16} - \frac{t^3}{6} - \frac{12t^2}{2} + C\). Find

  1. the equation determining the rest times in terms of \(C\), explaining why numerical rest times cannot be specified,
  2. an expression for the displacement of the particle from \(O\),
  3. displacement from \(O\) at \(t = 1\).

The constant \(C=v(0)\) is not assigned a numerical value. Express your answers in terms of \(C\), with \(t\ge0\).

Solution:

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Answer:The constant \(C\) is undefined, so the rest time is not numerically determined. If the initial displacement is \(1\text{ m}\), then (ii) \(s=\dfrac{t^5}{80}-\dfrac{t^4}{24}-2t^3+Ct+1\); (iii) when \(t=1\), \(s=C-\dfrac{247}{240}\).

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