3.1 Exercise 11

The position of a particle moving along the x-axis is given by $x \left(t\right) = 4.0 - 2.0 t$ m. (a) At what time does the particle cross the origin? (b) What is the displacement of the particle between $\text{t} = 3.0 \text{s}$ and $\text{t} = 6.0 \text{s} ?$