# Newtons does a 40 kg bag of stones weigh

espo
how much in newtons does a 40 kg bag of stones weigh? my answer is 302 newtons is that correct?

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chroot
Staff Emeritus
Gold Member
Hi espo,

Just think about Newton's second law,

F = ma

If you have a bag of stones with a mass of 40 kg, and that bag of stones is in Earth's gravitational field (and thus has an acceleration of 9.8 m/s), then it must exert a force of 40 * 9.8 newtons on the ground. This force is what we call weight.

The bag weighs 40 * 9.8 = 392 N. Perhaps you typed 302 accidentally, when you meant to say 392?

- Warren