How to share this Lesson/Activity with your Google Classroom:
- To share this lesson/activity with Google Classroom, click "Continue with Google" to get started.
- After logging in, click "Add to Google Classroom" to assign this lesson/activity to your students.
Read the Following Selection
Read the following selection, or click on the play button below to listen aloud.
Four Types of Internal Forces
An internal force is a force that acts from within the structure.
Let us look at four types of internal forces.
Imagine that we start with a rectangular block of material.
Compression is a pushing force that squeezes a material.
This force often makes materials shorter.
Example: Hold a soft sponge flat in the palm of one hand.
Push down on the top of the sponge with your other hand.
You are creating compression.
Tension is a pulling force that stretches a material. This force often makes materials longer.
Example: Hold one end of an elastic band in each hand. Move your hands farther apart. You are creating tension that stretches the elastic band.
Torsion is a twisting or turning force.
Example: To wring out a wet washcloth, you use the twisting force of torsion. You hold the washcloth in two hands and twist it in opposite directions to force out the water.
Bending is a force that makes a straight material curved. One side of the material squeezes together (compression). The other side stretches apart (tension).
Example: A soft or damp sponge is easy to bend. Hold it in both hands and bend it in the same way as shown in the diagram. Tension acts on the top side and compression acts on the bottom side.
Now, show what you know!
Complete some questions about the reading selection by clicking “Begin Questions” below.
0 of 5 questions completed
You have already completed this activity. You cannot start it again.
Activity is loading…
You must sign in or sign up to take this activity.
You must first complete the following:
0 of 5 questions answered correctly
Time has elapsed.
You have reached 0 of 0 point(s), (0)
Score: of ()
0 Essay(s) Pending (Possible Point(s): 0)
1. Ling loves sleeping on her new mattress. Her old mattress was as hard as a board. The new mattress sinks comfortably under her when she climbs into bed.
What type of internal force acts on the mattress when she lies on it?CorrectIncorrect
2. Rick tunes his guitar. Rick tightens a guitar string to make it play in tune. To tighten it, he turns the tuning peg at the end of the guitar string.
What type of internal force acts on the guitar string?CorrectIncorrect
3. Rick tunes his guitar. Rick tightens a guitar string to make it play in tune. To tighten it, he turns the tuning peg at the end of the guitar string.
What type of internal force acts on the tuning peg?CorrectIncorrect
4. Maria and her brother Marco are making a fall wreath for their door. The first step is to take a straight piece of wire and make it into a circle.
What type of internal force acts on the wire as they make it into a circle?CorrectIncorrect
5. Mr. Green is fishing and a big fish has taken the bait. The fish tries to swim away as Mr. Green tries to reel it in.
What type of internal force acts on the fishing line?CorrectIncorrect