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

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

You must remember the definition of a moment: the Moment, measured in Nm, is equal to the Force applied, F, (N) multiplied by the perpendicular distance, d, from the axis of rotation and the line of action of the force.

Always state the principle of the sum of moments - for an object in equilibrium, the clockwise and anticlockwise moments are equal.

Make sure to to notice how the rod, or beam, ect is described in question - is it massless? If it has mass, is it uniformly distributed? Is it rigid?

Always be looking out for forces not perpendicular to the direction of rotation, you might have to use trigonometry here.

Fulcrum/Pivot: the point the moment is calculated about

Resultant moment: the sum of all the moments in the system

Equilibrim: when the moment at any single point along the object which in on a fulcrum has a moment of 0Nm

Centre of mass: if the weights on the system are not point masses, you may need to find where their centre of mass is- the point where a point mass could go to replicate the exact same moment they would produce

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) )

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 :)

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".

Moment = force × distant

Moment is measured in Newton Metres (Nm)

Force is measured in newtons (N)

Distance is measured in metres (m)

Moments is the turning effect of a foce about a fixed point called pivot. Moment is a vector quantity. Formula: Moment = Force X Perpendicular distance from the pivot. Unit of Measurement is Nm.

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

Moment about a point is the Force multiplied by perpendicular distance from the pivot point. Moments are measured in Newton metres. You must always include the direction of the moment, that is either clockwise or anticlockwise. The distance must always be perpendicular from the pivot to the force itself.

When discussing moments in Paper 2, key terms to use include moment of a force (Moment=Force×Perpendicular Distance from the Pivot\text{Moment} = \text{Force} \times \text{Perpendicular Distance from the Pivot}Moment=Force×Perpendicular Distance from the Pivot), perpendicular distance, line of action, and pivot. Mention the Principle of Moments: "For equilibrium, the sum of clockwise moments equals the sum of anticlockwise moments." Use terms like center of mass, couple (equal and opposite forces causing rotation), and torque (rotational effect of a force). Always specify the direction (clockwise/anticlockwise) and ensure distances used are perpendicular.

The force applied and the perpendicular distance from a point or an axis through that point.

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)

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.

• 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