I keep getting “Universal law of gravitation” questions wrong in Gravitation. What's the trap?
forgetting the force depends on 1/r² — doubling the distance quarters the force.
The usual trap: forgetting the force depends on 1/r² — doubling the distance quarters the force. How to avoid it: it's an inverse-square law, so distance matters a lot. Go back to the definition — every two masses attract with F = G·m₁m₂/r² along the line joining them.
Key point
Universal law of gravitation
Common mistake
forgetting the force depends on 1/r² — doubling the distance quarters the force.
Memory tip
it's an inverse-square law, so distance matters a lot.
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