Failure is not scary; what's scary is losing the ability to learn from it.
The only thing that can stop you is you.
The biggest risk is not taking any risk. In a world that's changing really quickly, the only strategy that is guaranteed to fail is not taking risks.
物体的加速度与所受的合外力成正比,与物体的质量成反比。加速度的方向与合力的方向相同。