图中显示了一辆汽车在两个公路交叉口之间行驶的速度-时间图像。
阴影区域表示行驶的距离。
行驶的距离为 1620 m。

它不会直接告诉你答案，而是问你卡在哪一步看看 AI 是怎么陪你一步步弄懂这道题的

完整解法

1. Relate the distance travelled to the triangular area under the speed-time graph.

Distance travelled $=$ area under speed-time graph.

$\frac{1}{2}\times 72\times v=1620$

2. Solve the equation to find the greatest speed.

$36v=1620$

$v=\frac{1620}{36}=45$

答案

$v = 45\text{ m/s}$

1. Use the proportional relationship on the straight-line part of the speed-time graph.

From part (a), the greatest speed is $45\text{ m/s}$ at $48$ seconds.

For the first $48$ seconds, the graph is a straight line from $(0,0)$ to $(48,45)$ , so
$\frac{\text{speed at }32\text{ s}}{45}=\frac{32}{48}.$

2. Calculate the speed after $32$ seconds.

$\text{speed at }32\text{ s}=45\times \frac{32}{48}=30$

答案

$30\text{ m/s}$

1. Calculate the decrease in speed per second over the last 24 seconds.

For the last $24$ seconds, the speed decreases from $45\text{ m/s}$ to $0\text{ m/s}$ .

$\text{deceleration}=\frac{45-0}{24}=1.875\text{ m/s}^2$

答案

$1.875\text{ m/s}^2$

AI 分析，可能出错

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