This coefficient μs is just a number, usually between 0 and 1, which you can look up in a table for all kinds of different materials. For rubber tires on asphalt, it’s 0.9; for tires on ice it falls to 0.15 (hence snow chains). And N, as we saw above, equals the gravitational force, which in turn depends on the object’s mass. The greater the mass, the more friction you get.
Фото: Joeri Mostmans / Shutterstock / Fotodom。关于这个话题，新收录的资料提供了深入分析
Москвичам назвали срок продолжения оттепели14:39，更多细节参见新收录的资料
She recommends that anyone who finds bats in a building should contact the National Bat Helpline for advice.，详情可参考新收录的资料