Page 407-408

1. Page 407-408 Review Key Terms

2. 1.a • 2. c • 3. c • 4. a • 5. a • 6. equal force acting on an object in opposite direction. • 7. the types of surfaces involved.

3. 8. the object’s masses and distance. • 9. the leaf has greater surface area. • 10. it moves based on its mass and velocity. • 11. The force the four children are exerting on the object balanced one another. • 12. Fluid friction usually less than sliding friction. By bathing the parts of the machine in oil, friction is reduced.

4. 13. The yo-yo exerts a downward force on the string. Whatever or whomever is holding the string exerts an equal upward force. • 14. Newton’s second law states that force is equal to mass multiplied by acceleration. • 15. You can throw your empty jet pack away from the space station. As result, the reaction force exerted on you by the jet pack will accelerate you toward the space station.

5. 16. Student’s drawings should resemble the art in figure 21, with Earth’s gravitational force directed toward the center of Earth and perpendicular to the satellite’s motion. Yes, the satellite is accelerating because it is changing direction. • 17. When you squeeze a sponge you use compression

6. 18. The skateboard stops, but your inertia causes you to keep moving forward. • 19. The net force is 90N to the right. The acceleration is 9m/s/s. • 20. The friction force is equal to the pushing force because the book moves at a constant velocity.