Moments of a forceEdexcel International A Level Maths: Mind map

Exam questions on Moments of a force

1. A light rod $AB$ of length 2 m is horizontal. A vertical force of 15 N acts downwards at $B$, and a vertical force of 24 N acts upwards at the point $C$ on the rod, where $AC=0.5$ m.
   The 24 N force is moved to a point $D$ on the rod, so that the total moment of the two forces about $A$ is zero. Find $AD$.2 marks
2. A uniform plank $AB$ of length 4 m and mass 30 kg rests horizontally on two supports, one at $A$ and one at $B$. Take $g=9.8$ m s$^{-2}$.
   With the man still standing in that position, find the reaction of the support at $A$.2 marks
3. A uniform rod $AB$ of length 3 m and mass 8 kg is held in a horizontal position by two vertical light strings, one attached at $A$ and the other attached at the point $C$ on the rod, where $BC=1$ m. Take $g=9.8$ m s$^{-2}$.
   Find the tension in the string at $A$.3 marks