What terminology do I need to make sure I use for Moments in Paper 2?

• the turning effect a force has around a point is a moment,
• A force must act upon an object so that the body would begin to turn,
• Moment = Force X Perpendicular Distance,
• For aan object to be in equilibrium the total moments must be equal,
• The weight of an object operates through its centre of mass

The moment of a force measures the turning effect of the force upon a rigid body. It is defined as the product of the magnitude of the force and the perpendicular distance from the axis of rotation. The moment is a vector with unit of Nm

The terminology that needs to be used for moments in paper 2 are perpendicular distance, pivot, force, torque, centre, equilibrium, uniform, and beam. When figuring out moments, you have to figure out the perpendicular distance from the pivot to the line of action of the force. You also have to check if the beam is uniform or not and if the pivot is at the centre or not. If it is not at the centre you also have to account for the weight of the beam. If it is at a different angle, you have to us ethe angle to find the horizontal or vertical component and use the perpendicular distance from there.

You should make sure you understand that moments have direction. You need to find a direction for the force and also look at the distance in perpendicular direction.

Hi Roberta,

Some key terms you want to make sure you use are:

1. Taking moments 'about' a point (this is the point from which you measure your 'distance' used in the moment equation. It is usually the hinge or pivot)
2. Force and its line line of action (the line along which the force acts)
3. The moment arm (the perpendicular distance between the point you are taking moments about and the line of action of the forc)

Hi Roberta,

Moment is newtons (force) multiplied by Meters and it is very important to notify which direction (anticlockwise or clockwise) is the positive direction, otherwise, it is very easy to mix things up!

Make sure to always use newton/metres as your units when working out the size of the moment. It is also good to list the formula for moments which is force (newtons) x distance (metres).

You should also know that when in equilibrium, the Anti clockwise moment = clockwise moment.

Identify major areas of concern in the draft essay during revising

Moments = force X perpendicular distance from the force to the point you are measuring the moment

The moment around any given point due to a force is the product of the perpendicular distance between the force and pivot, and the size of the force itself.

The key phrase is "perpendicular distance".

Start the question stating what you are going to do e.g. Take moments about A. Make sure you have a clear diagram and each point is labelled. Then take moments and anti-clockwise and set the two equal to each other if the system is in equilibrium.

Heya Robert! When a moments question comes up, ensure you write exactly what you're doing. A good example of this is stating 'taking moments anticlockwise about Point A', and then writing 'taking moments clockwise about Point A'. Later on in the working out, you can also safely write 'Anticlockwise moments = clockwise moments'

Terminology for Moments. There can be lots terminology that can be used, Im assuming it's pure 2 as your enquiry is in regards to paper 2, so it highly be likely to involve friction. Usual questions can be something to do with finding out if the friction will be sufficient enough to hold an object on a plane for instance once a supporting /external force is removed, in this application I would say working out will be your best friend as well as explaining your steps. When it comes to mechanics always apply the line rule in your working out to ensure its nice and clear for your teacher, examiner and yourself to look back on, to spot any potential mistakes :)

You should know the principle of moments ( which states that when a beam is in equilibrium under the action of several forces, the sum of all the clockwise moments must be equal to the sum of all the anticlockwise moments about a turning point (pivot) )

Sum of anticlockwise moments = sum of clockwise moments.