Explain to me how to use these physical formulas and their significance (I'm a senior one) 1. F = ma and f-f = ma 2. F = friction coefficient n = friction coefficient mg How are they used, how are they equal, what are the differences in usage and what are the meanings in physics? The symbol "friction coefficient" can't be worked out

F "- F = ma. F" is external force, a is acceleration. F "- F = ma. F is friction. F" is external force
Friction force F = gravity (or component force of gravity) mg * friction coefficient n
N is an empirical parameter, weight will be given or solved

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