[问答题]
A particle P moves along a str
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,/ 7kav.q)r*wrp(qwwdki+u ught line so that its velocity, $v \mathrm{~ms}^{-1}$ , after t seconds, is given by $v=\sin 3 t-2 \cos t-2 $, for $0 \leq t \leq 6$ . The initial displacement of P from a fixed point O is 5 metres.
1. Find the displacement of P from O after 6 seconds.
The following sketch shows the graph of v .
2. Find when the particle is first at rest.
3. Write down the number of times the particle changes direction.
4. Find the acceleration of P after 2 seconds.
5. Find the maximum speed of P .
