Study Guide – Chapter 9 Motion
and Buoyancy
Key Terms are underlined and in bold. You need to know the definitions and examples/explanations for all key terms.
1. Buoyancy (pages 424 – 429)
A. Buoyancy is the ability to float
B. Buoyant Force is an upward force that is exerted by a fluid. Buoyant force acts in an opposite direction to gravity.
C. Archimedes’ Principle states that the buoyant force acting on a submerged object is equal to the weight of the volume of fluid displaced.
D. Be able to describe why a huge metal ship, like an aircraft carrier, is able to float, while a chunk of metal isn’t.
E. Be able to describe why the Titanic sank (or your overloaded aluminum foil boats) using density and buoyancy.
2. Describing Motion (Pages 338 – 341)
A. What is motion?
B. What is a reference point? Why is it important for the reference point to be a stable object?
C. If objects are moving together (like you when you drive home from school with your parents or a carpool) are they in motion relative to each other (relative motion)?
D. What are distance and displacement? Be able to label on a map.
3. Speed and Velocity (pages 342 – 347)
A. What is speed? Know that speed is calculated with the formula
speed = distance/time. Be able to solve speed problems.
B. Average speed is the total distance covered divided by the total time covered.
C. Velocity is speed in a direction. The formula for calculating velocity is the same as for speed but you need to add a direction.
D. Be able to read graphs showing Time and Distance like the graphs on pages 346 and 347. You need to be able to describe the motion at each point.
E. On distance and time graphs, the steeper the slope, the faster the object is moving. The shallower the slope, the slower the object is moving.
4. Acceleration (pages 352- 355)
A. Acceleration is the rate at which velocity changes. If speed changes (faster or slower) OR direction changes, then an object has accelerated.
B. Be able to read a distance vs. time graph for acceleration like the one on page 355.
C. IF I give you an extra credit questions, it may be to figure out the acceleration of an object given the velocities and total time like the zip line lab in class. See page 353 for practice.
5. Energy (pages 358 – 363)
A. Energy is the ability to do work. Work is what is required to put an object in motion.
B. Potential Energy is stored energy. Be able to describe chemical, elastic and gravitational potential energy in real-life situations.
C. Gravitational potential energy depends on the height of an object and its weight. The more massive the object and the height of the object will determine the amount of potential energy.
D. Kinetic Energy is energy of motion. As an object falls is gains kinetic as it loses potential. Energy is transformed. Kinetic energy depends upon mass and speed but speed really affects the moving energy of an object.
E. The Law of Conservation of Energy says that energy cannot be created or destroyed, it only changes form. Be able to apply this law to the roller coasters we build in class, to how a pendulum moves, and also to explain why the pendulum CAN’T hit you in the face if you let it go from the tip of your nose.
6. Review Concepts - Chapter 1 (pages 6-26)
I may ask questions about these concepts that have already been tested. You can use your old study guide (find a copy online) to get more information.
A. Scientific Equipment
B. Scientific Inquiry (Hypothesis, Manipulated /Independent Variable, Responding/Dependant Variable, Controlled Variables, Controlled Experiment, Scientific Theory)
C. Measurement – (Know the definitions and units used to measure mass, length, volume, and time.)
D. Know what density is and how it is different from weight. Additional information on density can also be found in the section with buoyancy (pages 424-429).
