[填空题]
A particle P starts from a fixed point O a6j 6.)6pp knb5ti kgxdnd in9f s n1*4iuomoves along a horizontal straight line. Its veloc *n1onu4s9 ifiity v $\mathrm{~ms}^{-1}$ after t seconds is given by
The following diagram shows the graph of v .
1. Find the initial velocity of P .
v(0)= ms$^{-1}$
2. Find the acceleration of P during the first second.
a= ms$^{-2}$.
3. Write down the number of times the particle changes direction in the first 8 seconds. Justify your answer.
4. Find the total distance travelled by the particle in the first 8 seconds.
d= m .
