1. Unit 1 - Motion in a Straight Line

2. What is Motion? What is the physics of motion all about? Motion is part of the everyday physical world. We learn to walk, run, and drive without a formal understanding of the physics of motion. We do, however, have an intuitive idea of motion and its effects and causes. Motion involves a change in the position of an object over time. Motion can be described using mathematical relationships. Many technologies that apply concepts related to motion have societal and environmental implications.

3. What is Motion? Everything in our universe is in a state of motion: Our solar system moves through space. Earth revolves around the Sun while rotating about its own axis. People, animals, air, and countless other objects move about on Earth’s surface. The elementary particles that make up all matter, too, are constantly in motion. Physicists call the study of motion kinematics.

4. 1.1 Distance, Position, & Displacement To understand the motion of objects, we must first be able to describe motion. Physicists use a number of specific terms and units to describe motion. Physical quantities can be classified as either scalar quantities or vector quantities. A scalar quantity has magnitude (size) only. For example, a distance of 2.5 m, a speed of 23 m/s, a time interval of 15 s. A vector quantity has magnitude (size) and also a direction. For example, a displacement of 2.5 m[N], a velocity of 23 m/s[E], a force of 15 N[S]. Directions for vectors are often expressed in square brackets. An arrow above a variable indicates it is a vector quantity.

5. 1.1 Distance, Position, & Displacement The position of the school is 500 m [E] of home. The position of the school is 700 m [W] of the library.

6. 1.1 Distance, Position, & Displacement

7. SP #1-4 p.10-11

8. 1.1 Vector Scale Diagrams Earlier we used algebra do determine the displacement of an object in a straight line. Vector Scale Diagrams are another method we can use to solve displacement problems. A vector is physically represented using a directed line segment. A directed line segment has a tail at its starting point and a tip at its endpoint.

9. 1.1 Vector Scale Diagrams

10. 1.1 Homework Practice # 2,3 p.11 Practice # 2 p.13 Questions #1-4, 5bd, 6 p.13