3.1: Particle kinematics with column vectors

0606/12/F/M/22 — Question 8 · 8 marks

In this question, all lengths are in metres and all times are in seconds.
A particle AA is moving in the direction (2021)\begin{pmatrix} -20 \\ 21 \end{pmatrix} with a speed of 5858.
(a)
Find the velocity vector of AA.
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(b)
Given that AA is initially at the point with position vector (53)\begin{pmatrix} 5 \\ -3 \end{pmatrix}, write down the position vector of AA at time tt.
[1]
(c)
A particle BB starts to move such that its position vector at time tt is (35t+444t2)\begin{pmatrix} -35t + 4 \\ 44t - 2 \end{pmatrix}.
Find the displacement vector AB\overrightarrow{AB} at time tt.
[2]
(d)
Hence find the distance ABAB, at time tt, in the form pt2+qt+r\sqrt{pt^{2} + qt + r}, where pp, qq and rr are constants.
[2]
(e)
Find the value of tt when the distance ABAB is 66, giving your answer correct to 22 decimal places.
[2]