Simple Machines

Criteria for Success I will be able to name the six (6) types of simple machines. I will be able to calculate mechanical advantage given the work input and work output. I will be able to calculate work given force and distance.

Simple Machines Machines are objects that make it easier for people to do work. Simple machines have only one or two main parts. Examples: shovel, screwdriver, knife, broom, slide

Using a screwdriver to get the lid off a paint can… You do work on the screwdriver. The screwdriver does work on the lid.

Mechanical Advantage: Work input=the work you do on a machine Work output=the work done by a machine Machines allow for the same amount of work but less force.

Simple Machines Study Guide

1. Levers: A bar that pivots or turns on a fixed point. A fulcrum is the fixed point. Examples: seesaw, wheel barrel, fishing pole 1st Class—seesaw 2nd Class—wheel barrel 3rd Class—hammer

2. Pulley Consists of a wheel over which a rope, chain, or wire passes Example: opening the blinds

3. Wheel and Axle Consists of two circular objects of different sizes Example: Faucet, doorknob, steering wheel

4. Inclined Plane A straight, slanted surface Example: Ramp

5. Wedge A pair of inclined planes that move Example: knife, doorstops, axes

6. Screw An inclined plane that is wrapped in a spiral around a cylinder Example:

Compound Machine Made up of more than one simple machine Example: can opener

Label the simple machines in the following compound machine. Lever Wheel and Axle SCREW Pulley

What is work? Work is done when a force causes an object to move in the direction of the force. Example: Bowling is work. You are exerting force on the bowling ball. The bowling ball is traveling a distance in the same direction as the force of your arm.

During work, there’s a transfer of energy. Force vs. Work… applying force doesn’t always result in work

For work to be done, the object must move in the same direction as the force.

Can you calculate work? YES Work = Force x Distance W = F · d Work (energy) = Joules Force = Newtons Distance = Meters

Let’s practice… Work = Force x distance Work = 1,000 N x 150 meters How much work is done by a crane that lowers 1,000 N of material a distance of 150 meters? Work = Force x distance Work = 1,000 N x 150 meters Work = 150,000 Joules

Let’s practice… Work = Force x distance Work = 5.8 N x 2 m A boulder weighing 5.8 Newtons is lifted 2 meters. How much work is done? Work = Force x distance Work = 5.8 N x 2 m Work = 11.6 Joules

Your Turn! 1. If a car is moved 10 meters and 3 Newtons of force is needed to move the car, what amount of work has been done? 2. If a ball is lifted 2 meters off the ground and 5 Newtons of force were needed to move it, what amount of work has been done? 3. The force required to move a chair 4 meters is 3 Newtons, what amount of work is done?