Chapter 5.7, Problem 36ES

In these exercises assume that the object is moving with constant acceleration in the positive direction of a coordinate line, and apply Formulas $\left(10\right)$ and $\left(11\right)$ as appropriate. In some of these problems you will need the fact that $88\text{ ft/s}=60\text{ mi/h}$ .

A sprinter in a $100\text{ m}$ race explodes out of the starting block with an acceleration of $4.0{\text{ m/s}}^{\text{2}}$ , which she sustains for $2.0\text{ s}$ . Her acceleration then drops to zero for the rest of the race.

(a) What is her time for the race?

(b) Make a graph of her distance from the starting block versus time.