Download Ch. 23 Review sheet answers 1. Every force has an opposite force

Ch. 23 Review sheet answers 1. Every force has an opposite force. 2. Motion is a change in position. 3. The force that opposes motion is friction. 4. Speed is rate of change of position. 5. An unbalanced force acting on an object causes it to accelerate. 6. When two birds are pulling on a worm and the worm moves toward the first bird, you know that the forces are unbalanced. 7. The unit of force is the Newton. 8. Inertia is a measure of the mass of an object. 9. You hear that a storm is moving 15 km/h north. You have been given the storm’s velocity. 10. You travel 200 km in 2 h. Your average speed is 100km/h. 11. When a car slows down at a traffic light, it is accelerating. 12. Speed is the distance traveled divided by the time needed to travel the distance. 13. A horse speeds up from a speed of 15 m/s to 30 m/s in 3 seconds. What is the horse’s acceleration? 5 m/s2 14. A bicycle coasting downhill travels 10 m in 5 seconds. What is the bicycle’s average speed? 2 m/s 15. A force is a push or a pull. 16. Displacement divided by time equals velocity. 17. The distance between starting and ending positions is called displacement. 18. Weight depends on the force of gravity on an object. 19. You throw a ball into the air. As the ball leaves your hand, the forces acting on it are gravity and your hand. 20. Static friction keeps you from sliding off a sled when it starts moving. 21. Velocity indicates direction. 22. Inertia increases when mass increases. 23. Static friction pushes you forward when you walk. 24. If the action force on an object is 5 N to the left, what is the reaction force? 5 N to the right. 25. Magnetic force, electric force, and gravity are examples of long-­range forces. 26. The gravitational force between two objects depends on their masses and separation. 27. The unbalanced force of a football is 5 N downward. Therefore, its acceleration is downward. 28. When the forces on an object are balanced the object moves at a constant velocity. Cats pause: 1. An element is a pure substance that cannot be separated into simple substances by physical or chemical means. 2. What are the four states of matter? Solid, liquid, gas plasma 3. Sodium chloride is an example of a compound. 4. Density depends on mass and volume. 5. How would you measure the volume of a screw? Graduated cylinder with water. Water displacement. 6. An experiment is a series of carefully planned steps used to test a hypothesis. 7. A farmer sets up an experiment to find out if cow manure as a natural fertilizer would produce more tomatoes than Miracle Gro fertilizer. What is the independent variable in this experiment? Fertilizer.