THERE ARE DIFFERENT TYPES OF FORCES

1 [1] FORCES AND MOTIONTHERE ARE DIFFERENT TYPES OF of the FORCES are more obvious than others and they can be broken down in to two DIFFERENT TYPES : FORCES are what make things move, like a push (kicking a football), or a pull (train)ELECTRICAL FORCES - Static electricity is an example of an electrical force . You will all have noticed that when comb your hair repeatedly that the comb attracts stray strands of hair. Static electricity can cause sparks and crackles if you take off a jumper made from man-made fibres (find out what they are).

2 MAGNETIC force - We all have played with magnets and discovered the invisible force that can either attract or repel another magnet or object made of iron or steel. It is the Earth s magnetic field that we track on a FORCESGRAVITY - Gravity is a force that pulls objects and people towards the Earth. It pushes things down wherever they are, whatever their size. Gravity is the force that gives us weight.[2]MASSThe mass of an object is the amount of matter that is in the object, so mass is related to how much stuff THERE weight of an object is the force OF GRAVITY that acts on that object, so weight is related to the pull of the AND WEIGHTThe mass of an object (measured in Kg) is the same no matter where it islocated in the universe.

3 The weight of an object (measured in Newtons) will vary depending where in the universe it is AND MOTIONCONTACTFORCESFRICTION - This is the force that resists things rubbing against each other. It helps you walk without sliding - except when you walk on the ice, THERE is very little friction and therefore you AND WEIGHTAIR RESISTANCE - This force slows things down when they are moving. Have you ever put your hand out of a car window when you are travelling along? If so you will have felt air resistancePULL (TENSION) - Have you ever had to compete in a tug-of-war competition or had to drag a heavy object?

4 Pulling is a force that we come across every dayPUSH (APPLIED force ) - Again, this is a force that we are all familiar with. Whether you are pushing a bike up a hill or simply shoving a plate across the table - you should be able to think of lots of (SPRING force ) - Whether you are screwing the top off a fizzy drink or turning a tap on to brush your teeth, spring FORCES are ones that you will be familiar with on a daily - This is the force that pushes things up in the water. It helps boats float and keeps swimmers from sinking.

5 (Who am I?)[3]BALANCED AND UNBALANCED FORCESF orces can be described as being balanced or the FORCES on an object are balanced: an object that is not moving will remain stillor an object that is moving continues to move at the same speed and in the same directionIf the FORCES on an object are unbalanced: an object that is not moving starts to moveor an object that is already moving changes speed or directionUNBALANCED FORCES CAUSE CHANGES IN SPEED OR DIRECTIONA ctivity:Have a look at the images in the panel down the side of the page.

6 Name the FORCES illustrated in each image and decide whether the FORCES are either balanced or FORCESF orce is measured in Newtons. A force of one Newton will give a mass of one kilogram, and an acceleration of one metre per second. This means that each second, its speed will increase by one metre per second. When measuring a force , you must state its direction, otherwise you do not know what effect it can show the FORCES acting on an object using a force diagram. In a force diagram, each force is shown as a force arrow.

7 The arrow shows the size of the force (the longer the arrow the bigger the force ) and also the direction in which the force OR UNBALANCEDS teady SpeedStanding StillWhat is the resultant force ?[4] FORCES AND MOTION ACTIVITIESIf you drop an object it will fall to the floor due to the force of gravity. If you place the same object on a a table it will not fall because the table produces an equal force upwards. However, if you place the object on a weak paper support, the support crumples and the object will fall to the floor because the force created by the paper platform is not as strong as the force of gravity.

8 So, when the object is on the table, the FORCES are balanced and when the object is on the paper platform the FORCES are unbalanced (therefore the object moves/changes speed in the direction of the bigger force ).Activity:Push a model car along a table, so that it slows down and eventually stops. What FORCES are acting on the car as it moves and stops? What are the opposing FORCES acting on the model car? When are the FORCES balanced and unbalanced?By reducing air resistance and friction FORCES that act on a car ( stream lining), what effects will these changes have on the speed, the amount of force required to accelerate the car, and fuel consumption of the car?

9 Design activity:Cars which create less friction use less petrol and are therefore less and draw a car, labeling and describing features you have changed to reduce air IN ACTIONLook at the images in the 4 boxes at the side of the page and label them your own pictures in these two boxes showing examples of the following FORCES : Gravity Air Resistance Pull Upthrust Friction PushWRITE THE NAME OF THE FORCES IN THE BOXES:DRAW AND LABEL YOUR OWN ARROWS:SPEEDS peed is calculated by the number of metres travelled per (metres per second) = distance (metres) x time (seconds) the speed of a car which travels 600m in 30 the distance travelled by a horse which runs 1 Kilometre in 4 the time it takes a man running 5m/s to run 450 m[5]HistoryIsaac Newton (1642-1727) was an English physicist, mathematician and astronomer who many people consider to be the greatest scientist of all time.

10 In his book, Principia, published in 1687, he described his 3 laws of motion which have dominated scientific study for over 300 years. English poet Alexander Pope wrote a very famous epitaph for Newton after his death: Nature and nature s laws hid in night; God said let Newton be and all was light. Einstein kept a picture of Newton in his on the MoonGravity is the force that gives us weight. Everything contains a certain amount of material called its mass. When you measure your weight you are really measuring the force of the Earths gravity pulling on your mass.