Mechanics and materials

What you'll learn

1. 1

   Think of a spring on a door closer. When you pull the door, the spring stretches — that's a force called tension pulling it apart.

2. 2

   What happens to a spring when you pull it?

3. 3

   Drag the blue block to stretch the spring — watch how the force arrow changes.

4. 4

   A steel rod in a building supports a heavy roof. Is it in tension or compression?

5. 5

   A rope holding a hanging lamp is under which force?

6. 6

   Tap the correct word to describe the force in a bridge cable holding up the deck.

7. 7

   Which material is best at resisting compression — concrete or rubber?