[填空题]
A particle P starts from a fixed point O and moves alq8c+(0ro s2mwhlhg l;s0oahq9 a50 gl8ffip-ong a horizond vor0t11y:a3byn.v mtal straight li.3bdm y 0yo1vv:1at rnne. Its velocity 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 .
