Force diagrams

The block on a surface but with an applied force, FL, to the left of 10 N and an applied force, F R, to the right of 20 N. The weight and normal also have magnitudes of 10 N.

Chipa Thomas Maimela‘s insight:

It is important to keep the following in mind when you draw force diagrams:

Make your drawing large and clear.

You must use arrows and the direction of the arrow will show the direction of the force.

The length of the arrow will indicate the size of the force, in other words, the longer arrows in the diagram (FR for example) indicates a bigger force than a shorter arrow (FL). Arrows of the same length indicate forces of equal size (FN and Fg). Use “little lines” like in maths to show this.

Draw neat lines using a ruler. The arrows must touch the system or object.

All arrows must have labels. Use letters with a key on the side if you do not have enough space on your drawing.

The labels must indicate what is applying the force (the force of the car) on what the force is applied (on the trailer) and in which direction (to the right)

If the values of the forces are known, these values can be added to the diagram or key.

See on everythingscience.co.za

A model of the iron sulphide crystal

Water (H2O), for example, is a compound that is made up of two hydrogen atoms for every one oxygen atom. Sodium chloride (NaCl) is a compound made up of one sodium atom for every chlorine atom. An important characteristic of a compound is that it has a chemical formula, which describes the ratio in which the atoms of each element in the compound occur.

Chipa Thomas Maimela‘s insight:

Compound

A substance made up of two or more different elements that are joined together in a fixed ratio.

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Components of vectors

Any vector can be resolved into a horizontal and a vertical component. If R  is a vector, then the horizontal component of R is R x and the vertical component is R y.

Chipa Thomas Maimela‘s insight:

A number of vectors acting together can be combined to give a single vector (the resultant). In much the same way a single vector can be broken down into a number of vectors which when added give that original vector. These vectors which sum to the original are called components of the original vector. The process of breaking a vector into its components is called resolving into components.

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Conservation of momentum

When they come into contact, ball 1 exerts a contact force on the ball 2, F B1, and the ball 2 exerts a force on ball 1, F B2. We also know that the force will result in a change in momentum:

Chipa Thomas Maimela‘s insight:

Definition 1: System

A system is a physical configuration of particles and or objects that we study.

Definition 2: Isolated system

An isolated system is a physical configuration of particles and or objects that we study that doesn’t exchange any matter with its surroundings and is not subject to any force whose source is external to the system. Definition 3: Conservation of Momentum

The total momentum of an isolated system is constant.

See on everythingscience.co.za