Review the key ideas from Lessons 16-20, then test yourself with 10 multiple-choice questions and 3 short-answer questions.
Quick Review
Focus: A force is a push or pull that can change an object's motion or shape. Forces can be contact forces or non-contact (action-at-a-distance) forces.
Key terms: Force, Newton (N), Contact force
Focus: Balanced forces produce no change in motion. The net force is the vector sum of all forces acting on an object.
Key terms: Balanced forces, Unbalanced forces, Net force
Focus: A fair test changes only one variable at a time while keeping all other conditions constant. Scientific investigations follow a method: aim, hypothesis, method, results, conclusion.
Key terms: Independent variable, Dependent variable, Controlled variable
Focus: Scientific explanations are based on evidence from observations, measurements, and experiments. Different types of evidence (qualitative, quantitative, experimental, observational) have different strengths.
Key terms: Evidence, Qualitative data, Quantitative data
Focus: Waves transfer energy; motion describes how objects move; forces cause changes in motion. The concepts in this unit are interconnected and can be applied to real-world phenomena.
Key terms: Synthesis, Depth study, Interconnection
Multiple Choice (10 questions)
1. What is the SI unit of force?
2. Which of the following is a non-contact force?
3. What is the net force when forces are balanced?
4. An object moving at constant velocity must have:
5. In a fair test, how many variables should be changed at a time?
6. The variable that is deliberately changed in an experiment is called the:
7. Which of these is quantitative data?
8. Why is repeatability important in science?
9. Which equation relates wave speed, frequency, and wavelength?
10. What does the gradient of a speed-time graph represent?
Short Answer (3 questions)
Hint: Think about whether the force requires physical touching.
Hint: Consider forward driving force, air resistance, friction, gravity, and normal force.
Hint: Consider what you would change, measure, and keep the same.
Put what you have reviewed to the test! Jump through the checkpoint questions in game form.
Play GameTick the box when you have finished the questions and played the game.