Changes

: The [[SI Unit|scientific units]] of [[force]] is the [[Newton]] (N). However, [[force]] can also be [[measure]]d in [[pound]]s ([[Pound|lb]]) and [[ounce]]s ([[Ounce|Oz]]).

: [[Force]]s can be represented in a [[diagram]] with arrows that show the [[magnitude]] and [[direction]] of the [[force]]. A bigger arrow means a bigger [[force]].

A '''force''' is a [[vector]] quantity that can affect the [[speed]], direction of motion or shape of an [[object]].

: A [[force]] can be is a [[measurevector]]d using a quantity because it has both [[Newton Metermagnitude]]and direction.

: When two [[force]]s act in opposite directions, along a line, one direction is chosen to be a [[Positive (Number)|positive]] direction and the other is chosen to be a [[Negative (Number)|negative]] direction, just as on a [[Number Line|number line]] in [[maths]].

|[[File:ForceNumberLineVertical.png|center|300px200px]]| style="height:20px; width:280px300px; text-align:center;" |If the 'up' direction is chosen to be [[Positive (Number)|positive]] then any [[vector]] pointing 'up' has a [[Positive (Number)|positive]] [[magnitude]] value and any [[vector]] pointing 'down' has a [[Negative (Number)|negative]] [[magnitude]]value.

In this [[diagram]] the green [[vector]] has a [[magnitude]] value of +2 while the red [[vector]] has a [[magnitude]] value of -4.

If the number lines represent the number of [[Newton]]s [[force]] then the [[Resultant Force]] is the two [[magnitude]]s values added together.

|[[File:ForceNumberLineHorizontal.png|center|600px400px]]

| style="height:20px; width:600px400px; text-align:center;" |If the 'right' direction is chosen to be [[Positive (Number)|positive]] then any [[vector]] pointing 'right' has a [[Positive (Number)|positive]] [[magnitude]] value and any [[vector]] pointing 'left' has a [[Negative (Number)|negative]] [[magnitude]]value.

In this [[diagram]] the blue [[vector]] has a [[magnitude]] value of +3 while the yellow [[vector]] has a [[magnitude]] value of -2.

If the number lines represent the number of [[Newton]]s [[force]] then the [[Resultant Force]] is the two [[magnitude]]s values added together.

| style="height:100px; width:200px; text-align:left;"|A [[boat]] is being pulled by two separate tug boats attached by a cable. The tension in each cable is 5000N.| style="height:100px; width:200px; text-align:left;"|The tug boats and cables are replaced by [[vector]] [[force]]s from the [[boat]].

| style="height:100px; width:400px; text-align:left;" colspan= "3"|This [[Scale Diagram]] shows that the two arrows add to make a length of 9.4cm, which represents 9400N, in a direction of 90° from the [[North]] which is an [[East]]erly Easterly direction.

| style="height:100px; width:200px; text-align:left;"|A [[boat]] is being pulled by two separate tug boats attached by a cable. The tension in each cable is 5000N.| style="height:100px; width:200px; text-align:left;"|The tug boats and cables are replaced by [[vector]] [[force]]s from the [[boat]].| style="height:100px; width:200px; text-align:left;"|One of the [[force]]s is redrawn as the [[hypotenuse]] of a [[Right Angle Triangle|right angle triangle]] with [[height]] in the [[y-axis]] and [[base]] in the [[x-axis]].

| style="height:100px; width:400px; text-align:left;" colspan= "3"|The total [[force]] [[North]] can be calculated by finding the [[height]] of each [[triangle]].

The [[force]] from the top tug boat is +1710N to the [[North]] and the force from the bottom tug boat is -1710N to the [[North]] so the total [[force]] [[North]] is zero.

The total [[force]] [[East]] can be calculated by finding the [[base]] of each [[triangle]].

The [[force]] from the top tug boat is +4698N to the [[East]] and the force from the bottom tug boat is +4698N to the [[East]] so the total [[force]] [[East]] is 9396N.