Speed or velocity at specific time

A question is this type if and only if the task requires evaluating the velocity vector or computing the scalar speed (magnitude of velocity) at a given specific value of t.

1 questions · Standard +0.3

Sort by: Default | Easiest first | Hardest first
AQA Paper 2 2020 June Q14
7 marks Standard +0.3
At time \(t\) seconds a particle, \(P\), has position vector \(\mathbf{r}\) metres, with respect to a fixed origin, such that $$\mathbf{r} = (t^3 - 5t^2)\mathbf{i} + (8t - t^2)\mathbf{j}$$
  1. Find the exact speed of \(P\) when \(t = 2\) [4 marks]
  2. Bella claims that the magnitude of acceleration of \(P\) will never be zero. Determine whether Bella's claim is correct. Fully justify your answer. [3 marks]