Pre-quiz: Unit 2 Earthquakes, Forces, and Energy

1. Where are you most likely to feel earthquakes?

• In the middle of continents
• Along plate boundaries
• Deep in the ocean
• Near volcanoes

2. What happens when unbalanced forces act beneath Earth's surface?

• The Earth becomes perfectly stable.
• The land stretches but doesn’t break.
• Stress builds, cracking and breaking the land.
• Mountains immediately form.

3. Which of these best describes why land moves on Earth’s surface?

• Magic!
• Tiny earthquakes we can’t feel.
• Forces from Earth's interior.
• Surface winds blowing dirt around.

4. What keeps a solid stable when forces are acting on it?

• Balanced forces
• A solid’s weight
• Only vertical forces
• Rapid rotation of Earth

5. If an object is stable, what can you say about the net force acting on it?

• The net force is greater than zero.
• The net force is zero.
• The object must be moving.
• Gravity stops affecting it.

6. Why do we use the Pythagorean theorem in free-body diagrams?

• To calculate total energy.
• To determine the direction of gravity.
• To break forces into components.
• To make the math more exciting!

7. When do solids deform or break under stress?

• When forces are balanced.
• When forces are unbalanced.
• When forces are removed.
• When gravity is zero.

8. What happens when you remove forces causing elastic deformation?

• Solids explode.
• Solids stay deformed forever.
• Solids snap back to their original shape.
• Nothing happens—it stays the same.

9. Why do unbalanced forces deep inside Earth cause surface changes?

• They create windstorms.
• They build up energy that leads to cracks and deformation.
• They make rocks grow larger.
• They make the crust softer.

10. What happens when too much energy is stored in fields during elastic deformation?

• The solid stretches infinitely.
• Bonds break, and cracks form.
• Particles freeze in place.
• The energy vanishes.