图（未按比例绘制）显示了一辆车的速度-时间图像。车辆从静止开始在 15 秒内匀加速到 20 m/s 的速度。然后它以该速度行驶，最后以 1 m/s^2 的加速度匀减速直至停止。

1. Find the uniform acceleration during the first 15 seconds.

Acceleration $=\dfrac{\text{change in speed}}{\text{time}}$

$a=\dfrac{20-0}{15}=\dfrac{4}{3}\text{ m/s}^2$

2. Find the speed after 10 seconds using the constant acceleration.

At $t=10$ s,

$v=0+\dfrac{4}{3}\times 10=\dfrac{40}{3}=13.333\ldots$

1. Find the time taken to decelerate from $20\text{ m/s}$ to rest.

Deceleration $=1\text{ m/s}^2$.

Time to decelerate
$=\frac{20}{1}=20\text{ s}.$

2. Express the total distance as the area under the speed-time graph.

Let the vehicle travel at $20\text{ m/s}$ from $t=15$ to $t=P-20$.

Total distance:
$\frac12(15)(20)+20[(P-20)-15]+\frac12(20)(20)=950.$

3. Solve the equation for $P$.

$150+20(P-35)+200=950$
$20(P-35)=600$
$P-35=30$
$P=65.$