Work and Simple Machines SWBAT define work; distinguish the different types of simple machines; explain how machines make work easier

Work is done when a force causes and object to move in the same direction as the force that is applied. What is work measured in? Joules, named after James Prescott Joule, who showed that work and energy are related Work Equation Work = Force x Distance W = Fd

Applying Math A weight lifter lifts a 500 N weight a distance of 2 meters from the floor to a position over his head. How much work did he do? In your groups try the following two problems: Using a force of 50 N, you push a computer cart 10 meters across the classroom floor. How much work did you do? How much work does an Olympic sprinter do while running a 200 meter race with a force of 6 N?

What is a machine? Simple machine a machine that uses only one movement. Compound machine a combination of simple machines. How do machines make work easier? Can change the size of force you apply Can change the direction of the force

Mechanical Advantage Mechanical advantage the number of times the applied force is increased by a machine. Mechanical advantage equation Mechanical advantage = force out force in MA = F o _ F i

Simple Machines Pulley is an object, like a wheel, that has a groove with a rope or cable running through it. Lever is a rod or a plank that pivots about a fixed point. The pivot point is called the fulcrum.

3 classes of levers First Class Lever The fulcrum is between the input and output force. Fulcrum Load Effort

3 classes of levers Second Class Levers The output force is applied between the input force and the fulcrum Load Effort Fulcrum

3 classes of levers Third Class Levers The output force is applied at the bottom end of the stick. Load Effort Fulcrum

Simple Machines Wheel and axle is made of two round objects that are attached and rotate together about the same axis. Inclined plane a sloped surface, sometimes called a ramp.

Simple Machines Wedge a moving inclined plane, with one or two sloping sides. It changes the direction of the input force. Screw an inclined plane that wraps around a post.