College Physics (Algebra-Based) · 免费预览
物理学：导论
物理学研究什么以及它为何重要：物理学的研究领域是能量、物质、空间与时间之间的相互作用，物理学在日常技术及其他科学中的作用，模型、理论、定律与原理之间的区别，以及经典物理学与现代物理学之间的界限。
1. What Physics Is
What Physics Is
2. Why Physics Matters
Why Physics Matters
3. The realm of physics
Which statement best defines the realm of physics?
4. Models, Theories, and Laws
Models, Theories, and Laws
5. What a model is
The planetary model of the atom pictures electrons orbiting the nucleus. Why is this called a model rather than a direct observation?
6. Classical and Modern Physics
Classical and Modern Physics
7. Applying a law quantitatively
A cart of mass is pushed with a net force of . Use Newton's second law to find the acceleration, and state the law in words.
8. Theory versus guess
A friend says "evolution is just a theory." In scientific language, what is a theory?
9. Law versus principle
Which statement best distinguishes a scientific law from a principle?
10. Limits of classical physics
Classical physics is an excellent approximation under everyday conditions. Which situation requires modern physics instead?
11. Newton's second law in symbols
Complete Newton's second law in symbols: the net force on an object equals its mass times its acceleration, written .
12. The classical speed limit
Classical physics applies only when matter moves at speeds less than about what fraction of the speed of light? Give the percentage.