lunes, 26 de enero de 2009

Pruebas del III Parcial

TEST 7
Octavo A y B : Lunes 2 de Febrero.

Contenido (Lessons)
-10-1 Forces at Work.
-10-2 Different Kinds of Forces.
-10-3 What Makes Things Fall?
-11-1 The Tools to Use.
-11-2 Estimating the Size of a Force.
(paginas: 217- 240, y S75-S77, S84-S86 )


Study Guide
1. What is force? A push or pull exerted by one object on another. In exerting a force there is an AGENT that exerts a push or pull and a RECEIVER.
2. Name the effects that forces have on objects: Change the shape of an object, give motion to an object at rest, and alter the speed or direction of an object in motion.
3. What is motion? A change in position of an object when compared wiht a reference point.
4. What is the differenc between velocity and speed? Speed simply refers to how fast an object is moving, velocity refers the speed and direction of the moving object.
5. What is acceleration? A change in the speed or direction of motion.
6. Name some types of forces: buoyand, magnetic, electrical, gravitational, elastic, and frictional.
7. What are non contact forces? are forces exerted by an agent that does NOT touch the receiver.
8 What are contact forces? are forces exerted by an agent that does touch the receviver.
9. Which forces are contact forces? Buoyant, elastic, and frictional forces are contact forces.
10. Which forces are non contact forces? Magnetic, electrical, and grivitational forces are noncontact forces.
11. List the agent, receiver and effect.
Example: Magnet and paper clips: the agent is the magnet, the receiver is the pile of paper clips and the effect is the magnet attracting the paper clips.
-Piece of paper falling down.
-Hand pushing a book.
- When you loss your balance.
12. List 5 examples of buoyant, gravitational ,electrical, magnetic, frictional, and elastic forces. In each case identify the agent and the receiver of the force and state the force's effect.
13. How is the motion of an object described? By comparing it with a reference point, which is an object that is considered stationary.
14. How is speed determined? By dividing the distance traveled from a reference point by the amount of time it takes to conver that distance. Practice the exercises.
15.What is friction? Is a force that opposes motion.
16. How is motion of an object determined? By all the forces that act on it.
17. Every object in the universe exerts an gravitational force on every other object. True
18. The size of a gravitational force depends on the masses of the objects involved and the distance between them. True.
19. The weight of an object changes with its location in the universe, but hte mass of an object remain constant. True.
20. What is gravitational force? a force that is dependent on mass, and causes objects to move toward each other.
21. What is mass? The amount of matter present in an object.
22. What is weight? The gravitational force exerted on an object.
23. Every object remains at rest or moves with a constant speed in a straight line unless acted on by some unbalanced force. True.
24. Force is equals to mass by acceleration, force and acceleration are proportional. True.
25 For every action there is an equal and opposite reaction. True.
26. What is Inertia? The resistance of a mass to any change in its motion.

No hay comentarios: