BRAINCAKEHow to Lift a Weight
Let W be the weight of the upper part of the body, T be the tension in the back muscles, W0 is the weight to be lifted and R is the reaction force from the hip and z is the perpendicular distance of T from the pivot.
The weights create anti-clockwise moments about the hip joint that is equal to Wdsinα+W0d0sinα perpendicular to the spine.
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Key terms in this lesson
- Moment
- The turning effect of a force about a pivot, equal to the force multiplied by the perpendicular distance from the pivot to the line of action of the force.
- Principle of moments
- For a body in rotational equilibrium, the sum of the clockwise moments about any point equals the sum of the anticlockwise moments about the same point.
More in Forces in Equilibrium
- Stable Equilibrium
- Tilting and Toppling
- Tilting
- Toppling
- Objects On a Slope
- Free Body Force Diagrams
- Triangle of Forces
- Condition for Equilibrium
All 20 lessons in Forces in Equilibrium · All AQA AS-level Physics topics