← ⚛️ Physics · usually met in Std 8-12
Three sentences that explain why a bus passenger lurches forward when the brakes go on, why a heavy trolley is hard to start, and why a boat moves backwards as you step off it.
The first law says a thing keeps doing what it is doing — still, or moving straight at a steady speed — unless a force acts on it. The bus stops; you do not, until the seat in front stops you. The second law puts a number on it: force equals mass times acceleration, so the same push moves a light thing more than a heavy one. The third says forces come in pairs: push on something and it pushes back on you, equally and in the opposite direction.
The third law is the most misread. The two forces in the pair never cancel out, because they act on two different objects. A rocket is not pushing against the air; it throws gas downward and the gas throws the rocket upward, which is why rockets work better in space, where there is no air to get in the way.
Want to see it moving? Search YouTube for “Newton's laws of motion” ↗ — we send you to the search rather than to one video, because a link to one video eventually rots.
This entry was written for Star Student in our own words — it is a summary, not a source. Here is where the people who actually hold these facts keep them. Go and check.
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