A car, while traveling on a horizontal road, experiences a sudden tire blowout. Assuming the car was initially moving at a constant speed, and the driver doesn't apply the brakes immediately, which of the following best describes the immediate change in the car's kinetic energy?

马克思主义认为，哪个阶级是推翻资本主义社会的主要力量？

在建设社会主义和谐社会的过程中，以下哪项措施最能直接体现‘公平正义’的原则？

若二次型$f(x_1, x_2, x_3) = x_1^2 + 2x_2^2 + 3x_3^2 + 2x_1x_2 - 2x_1x_3$的矩阵$A$的特征值为$3, 2, 1$，则该二次型的正惯性指数是多少？

毛泽东提出的‘另起炉灶’外交方针意味着什么？