Simple Machines Discuss: What simple machines do you know of? There are six simple machines Almost all complex machines work with combinations of these 6 simple machines
Simple machines make WORK easier! What is Work? In order for work to take place you need: a force applied to an object. that object has to move a distance in the same direction as the force being applied. Force (N) Distance (m) © KeslerScience.com
Making work easier Review: How do we measure work? Work= force x distance A simple machine allows the user to apply a smaller force over a larger distance to do work on an object AND/OR changes the direction of the force
How much work is needed?
Inclined plane The best example of an inclined plane is a ramp Less force is needed to do work on the object as the distance is increased
Every day inclined planes VIDEO!
Wedge A wedge is an inclined plane that moves. Force is applied to the wide end of the wedge and gets transferred to the sides.
Every day Wedges VIDEO!!
Screw A screw is an inclined plane wrapped around a cylinder. It takes less force to turn a screw than to pound a nail, however it takes more distance
Screw VIDEO!!!
Pulley A pulley is a wheel with a rope wrapped around it. The wheel rotates on a fixed axle. The rope rides in the groove of the wheel. All pulleys can change the direction of the force AND/OR decrease the force needed in exchange for distance Here are two types of pulleys Fixed and movable VIDEO
Pulley VIDEO!!
Wheel and axle A wheel and axle consists of a shaft, called an axle, inserted through the middle of a wheel. When force is applied to the wheel the force is magnified at the axle (due to the size difference) When force is applied to the axle the distance gets magnified
Wheel & Axle VIDEO!!
Lever A lever is defined as-----a rigid bar resting on a fulcrum (pivot), used to move a heavy or firmly fixed load with one end when effort (pressure) is applied to the other end. There are three classes of levers-
1st Class Lever A type of lever where the effort (force) is at one end, the FULCRUM (pivot) is in the middle, and the load is at the other end.
2nd Class Lever A type of lever where the fulcrum (pivot) is at the end, the LOAD is in the middle, and the effort (force) is at the other end.
3rd Class Lever A type of lever where the fulcrum (pivot) is at one end, the EFFORT (force) is in the middle, and the load is at the other end.
Compound Machines A compound machine is a machine that consists of more than one simple machine. Some compound machines consist of just two simple machines. For example, a wheelbarrow consists of a lever (2nd class) and a wheel and axle.
Let’s watch https://www.youtube.com/watch?v=E_ErI0QjNos