Physical Science State Assessment Review

1. Physical Science State Assessment Review S.HS.2B.1.1

2. Newton’s First Law of Motion (law of inertia) – an object in motion stays in motion at a constant velocity and an object at rest stays at rest unless acted upon by an outside force • This outside force is usually friction.

3. friction – a force that acts between two materials that are in contact with each other as they move past one another • The more smooth a surface is, the less friction it applies. • Only when friction is present do we need a force to keep the object moving. Without friction a moving object would never stop.

4. Types of friction: • sliding friction – when two surfaces slide past each other • rolling friction – when a round object rolls over a flat surface • fluid friction – friction between a fluid (any liquid or gas) and the surface of an object • Air resistance is a type of fluid friction.

5. Air Resistance: • All objects, regardless of their size or mass, accelerate toward the surface of the Earth at a rate of 9.8 m/s/s. • Gravity is the force that causes this acceleration. • As objects fall they experience friction with the air (fluid friction). • This air resistance is a force that acts in the opposite direction of gravity.

6. terminal velocity - – the point at which a falling object stops accelerating because the force of air resistance becomes equal to the force of gravity

7. Questions • 1. An object is pushed with a force and begins to move across a frictionless surface. Which best describes the object’s motion after the force stops acting? • A. constant velocity • B. increasing velocity • C. variable acceleration • D. decreasing acceleration

8. Questions • 1. An object is pushed with a force and begins to move across a frictionless surface. Which best describes the object’s motion after the force stops acting? • A. constant velocity – correct answer • B. increasing velocity • C. variable acceleration • D. decreasing acceleration

9. 2. An object is pushed with a force and experiences friction. Which best describes the motion of this object after the force stops acting? • A. constant velocity • B. increasing velocity • C. variable acceleration • D. decreasing velocity

10. 2. An object is pushed with a force and experiences friction. Which best describes the motion of this object after the force stops acting? • A. constant velocity • B. increasing velocity • C. variable acceleration • D. decreasing velocity – correct answer

11. 3. Which of the following statements best describes air resistance? • A. The rolling friction experienced between an object and the air. • B. A force of gravity. • C. The fluid friction experienced between an object and the air as the object falls. • D. The sliding friction experienced between an object and the air.

12. 3. Which of the following statements best describes air resistance? • A. The rolling friction experienced between an object and the air. • B. A force of gravity. • C. The fluid friction experienced between an object and the air as the object falls. – correct answer • D. The sliding friction experienced between an object and the air.

13. 4. Choose the surface or substance that would apply the greatest amount of friction. • A. air • B. a tile floor • C. a carpeted floor • D. motor oil

14. 4. Choose the surface or substance that would apply the greatest amount of friction. • A. air • B. a tile floor • C. a carpeted floor – correct answer • D. motor oil