## Mechanically Inclined

### Albert BaggottSanta Rosa District Schools

#### Description

Students use hands-on or demonstration activity to investigate the mechanical advantage of an inclined plane.

#### Objectives

The student solves single- and multi-step linear equations and inequalities that represent real-world situations.

The student knows that simple machines can be used to change the direction or size of a force.

#### Materials

For each group:
-Inclined plane apparatus
-Hall's carriage (cart)
-Weight container, can be improvised. (Polyethylene beakers or plastic cups work well. Punch holes in them with hot nails and tie string through the holes.)
-Laboratory balance
-Meter stick
-Weights, can be purchased or improvised (Some good weights are fishing weights, nuts. bolts, metal washers, paper clips and tire weights.Several of any type and a box of small paper clips should be sufficient.)
-String or cord, 6 ft per group.
(All of the above are available from most scientific supply houses.)
-Student (data) activity sheet, associated file

#### Preparations

1. Make sufficient copies of associated file.
2. Get out inclined planes, carts, weights, weight containers, laboratory balance, string or cord, and meter sticks.

#### Procedures

1. Set up the apparatus. This will usually be enough to stimulate interest and get the students' attention.

2. Ask students if it takes more force to push something up a gradual ramp or a steep ramp. Most will have had experiences and know that more force is required for the steep ramp.

3. Explain to the students that a simple machine has one or no moving parts and either multiplies the force applied or changes the direction of the force. The inclined plane is a simple machine because it multiplies the force applied and has no moving parts. The number of times the input force is multiplied is called mechanical advantage (MA).

4. Explain that weight (force) and mass are different. A laboratory balance measures mass. However, at any given location on Earth, mass and weight are directly proportional, therefore, we can use mass (grams) in our calculations instead of converting to weight (Newton's).

5. Divide students into groups if you intend this exercise to be hands on. Instruct students to set up the apparatus and follow the instructions for collecting data on their data sheets. Otherwise set it up as a demostration, in which case, you may wish to use students to assist you. Distribute the activity sheets.

6. When students have finished collecting data have them answer the questions and problems. You may want to assign this as homework. After they have finished the assignment, go over it and discuss it with them to help those who had trouble with the questions and problems. It is not necessary for all groups to do 4 trials. Some slower groups may do only 2 or 3, but the learning experience will be sufficient.

#### Assessments

Students use their data to calculate the mechanical advantage of inclined planes using the linear equations (definitions) given. (see attached worksheets) Students may need additional practice since this is a formative assessment for an introductory lesson. NOTE: Multi-step linear equations are not addressed in this lesson.

#### Attached Files

A diagram of the set up, data table, questions and problems.     File Extension: pdf