Mechanics · Forces & Newton's laws
Chapter 1 · 4
The idea
Forces on an inclined plane
Resolving the weight on a slope into components along (mg sinα) and perpendicular (mg cosα) to the surface, the normal reaction R = mg cosα, and applying F = ma along the slope (acceleration g sinα on a smooth slope).
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Mechanics · Forces & Newton's laws
Forces on an inclined plane
Resolving the weight on a slope into components along (mg sinα) and perpendicular (mg cosα) to the surface, the normal reaction R = mg cosα, and applying F = ma along the slope (acceleration g sinα on a smooth slope).
Why it works
Resolve along and into the slope
When a body sits or slides on a slope, gravity still pulls it straight down — but the motion is along the slope, so resolving horizontally and vertically is clumsy. The clean choice is to resolve along and perpendicular to the slope instead.The weight splits in two
For a slope at angle to the horizontal, the weight splits into two components:Keep reading — free
The rest of the explanation, plus 3 worked examples you step through move by move.
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