Simple Machines: Force is a push or a pull. The amount of force you have to use on an object depends on its mass. Motion is a change in position. Every motion is started by a force. Speed is how fast something moves over a certain distance. Work is the measure of force it takes to move an object a certain distance. Scientifically work is done only when an object is moved through a distance. Work=Force * Distance OR Joules= Newton * Meter WEDGE SCREW PULLY A special kind of wheel that changes the direction of the 1. Machine used for slicing, lifting, A screw is a machine with grooves force. When you pull down the object goes up. There are two types of Pulley. splitting, and holding. that winds round and round in a 1. A fixed pulley doesn't move when the rope is pulled. It spiral. is fixed to the upper bar. You can pull down on the rope in order to lift the load up. 2. A movable pulley. As the rope is pulled up, it can also move up. The weight is attached to this moveable pulley. Each side of the rope is supporting the weight, so each side carries only half the weight. The force needed to hold up the pulley in this example is 1/2 the weight! WHEEL AND AXEL INCLINED PLANE LEVERS Wheels are round, and they turn to A surface, often flat, set at an angle make things go. The wheel is one of to another surface (stairs or ramp) A lever is a simple machine consisting of a bar the most important inventions ever allows things to move up or down it. that pivots at a fixed point, called a fulcrum. made. We rely on it for almost all Levers are used to apply force to a load. The transportation. three classes of levers are based on the locations of the fulcrum, the load, and the input force. .