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Typo?Heya, Looking at an introduction to vectors. In my textbook it gives the example question: "A particle of mass 0.1 kg is held at rest on a rough plane inclined at 20° to the horizontal by a friction force, F, acting up the plane. Find the magnitude of F and the normal reaction."The given answer is: "F = 0.1 g sin20° = 0.335 N"Is this a typo, or is there something that I'm missing? Thanks very much as ever :) Theo ps can anyone explain what's happening with the units here? How do you get from grams * degrees to Newtons? |

Right. g is gravity, not grams. Gotcha. |

Might I add as an engineering instructor, if any of my students turned in a report with this in it, I would likely take points off and definitely reiterate the importance of clear communication. I would have accepted, "F = (0.1 kg) g sin 20°," or, better yet, "F = mg sinΘ = (0.1 kg)(9.807 m/s²)(sin 20°) = 0.335 N." |

Quote:
g is the acceleration due to gravity, not gravity (which is a force.)-Dan |

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