CK-12 Physical Science Concepts - For Middle School

http://www.ck12.org Chapter 4. Motion and Forces

Vocabulary

• machine: Any device that makes work easier by changing a force.

Explore More

Watch the video about simple machines at the following URL, and then answer the questions below.

http://nilma18.edu.glogster.com/simple-machines/

1. Which type of simple machine is a catapult?


2. What work does a catapult do?


3. How does a catapult make work easier?


4. How can you make a catapult with a spoon and ping pong ball?


5. The pivot point where a catapult turns is called the __.


6. Which playground equipment is the same type of simple machine as a catapult?
   a. swing
   b. teeter-totter
   c. slide
   d. all of the above

Review

1. What is a machine?


2. List three ways that machines may change a force.


3. Can a machine increase both the force and the distance over which the force is applied? Why or why not?


4. A broom is an example of a machine. Where are the input and output forces applied?


5. Look at the pictures of simple machines in theFigure4.79. Which type of simple machine is represented by
   each of the following tools?
   a. hammer
   b. ladder
   c. knife
   d. doorknob