Find the value of t when the particle is instantaneously at rest during the first 6 seconds of its motion. [2]
At t = 6, the particle hits a barrier at a point P and rebounds. Find the velocity with which the particle arrives at P and also the velocity with which the particle leaves P. [3]
Find the total distance travelled by the particle in the first 10 seconds of its motion. [5]
Solution
(a) To find when the particle is at rest, set the velocity \(v = \frac{ds}{dt}\) to zero. For \(0 \leq t \leq 6\), \(s = t^2 - 3t + 2\).
Differentiate: \(v = \frac{ds}{dt} = 2t - 3\).
Set \(v = 0\): \(2t - 3 = 0 \Rightarrow t = 1.5\).
(b) At \(t = 6\), find the velocity using \(s = \frac{24}{t} - \frac{t^2}{4} + 25\) for \(t \geq 6\).