Auto stopping distance
汽车制动距离
Under optimum conditions on a dry road, the coefficient of friction may be as high as 0.8, so that you could decelerate at 0.8g = 0.8 x 9.8 m/s^2 = 7.8 m/s^2.
a. If you are traveling at 55 mi/h (24.6 m/s), how long will it take you to stop?
b. How far will you travel while stopping?
在干燥的道路上，摩擦系数可能高达0.8，因此你可以以0.8g = 0.8 × 9.8 m/s² = 7.8 m/s²的加速度减速。a. 如果你以55英里/小时（24.6 m/s）行驶，要停下来需要多长时间？b. 刹车过程中你会行驶多远？
Solution:
解法：
All constant acceleration problems can be solved using the basic motion equations.
所有匀加速问题都可以通过基本运动方程解决。
| a. Using the basic motion equation
a. 使用基本运动方程 |  | , or solving for t,
，或解出 t， |  |
In the equation, v is the velocity at a chosen time t. In this problem the initial velocity is given, and you know that v=0 since it is the velocity at the time when you stop.
在方程中，v 是在选定时间 t 时的速度。在本题中，初始速度已给出，且已知 v=0，因为这是停止时的速度。
Examining the known and unknown quantities
 | leads to
导致 |  |
考察已知和未知的量
b. The stopping distance may be calculated from the motion equation:
b. 停车距离可通过运动方程计算：
Alternatively, the distance may be calculated from the combined motion equation form which eliminates the time from the calculation.
或者，可以通过结合运动方程的形式来计算距离，该形式消去了时间。
| Auto stopping distance discussion
自动停止距离讨论 | Example problems in mechanics
力学例题 |
Motion with constant acceleration
索引 匀加速运动
力学
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