What’s going on here?

Moments How to calculate the total moment about a pivot Understand how to resolve forces at an angle To be able to use moments to solve problems involving equilibrium of rigid bodies.

Moments Moments are the turning effect from a force about a point. These can be clockwise or anticlockwise. The magnitude of Moments are affected by two things. The magnitude of the force applied, and the distance from the pivot the force acts on.

Moments Moment = Force x distance from pivot Units? Newton-meters (Nm) Things to be careful about?

Example Find the moment generated by the 25N force about point A. 10m 25N 30 0 A Resolve Force into H/V components Find perp. distance

Dominoes Time! Have a go at the dominoes! Be careful about whether it’s clockwise or anticlockwise!

Extension ACB is a light rigid equilateral triangular framework of side 2m. Find the total moment of the forces about: (a) A (b) B (c) C AB C 5N 3N ABCD is a square lamina of side 3m. The total moment of the forces about the centre O is 27Nm. Find the value of F. A B C D O 2F F 0 Nm 5.20 Nm anticlockwise 8.66 Nm anticlockwise F = 6N

Equilibrium of Rigid Bodies A rigid body cannot be deformed by the forces acting on it. If one is in equilibrium, the following applies: the forces are in equilibrium; the moments are in equilibrium. In the case of moments, the clockwise moments must equal the anticlockwise ones

Balance out the Characters Balance out the set of characters so the moments are in equilibrium. The more you place, the harder it becomes. Make sure you show your working.

Discussion

Key Points Moment = Force x distance The force and distance used must be perpendicular. When an object is in equilibrium, clockwise moments must equal anticlockwise moments as well as the forces being in equilibrium.

Independent Study Exercise A Q1-6 & Exercise B Q1-2 Mymaths.co.uk: Moments Task (first half)