Chapter 1. Motion and Momentum SEC. 1 What is Motion? The Students Will: • Define Speed, velocity and displacement • Graph Motion Terms to Know • Speed • Average Speed • Instantaneous Speed • Velocity • Distance • Displacement What is Motion? • Movement--------- changes in position • Requires a point of reference (starting point) What is Distance? • The length of the route one travels Ex. Distance from your house ------ school Expressed in Meters (m)/ Kilometers (km) What is Displacement? • Includes the distance between the starting and ending points, and the direction in which you travel. Ex. 40 m east What is Speed? • The distance traveled divided by the time taken to travel the distance is called speed. S= distance (meters) time (seconds) Problem Solving Technique Strictly follow the steps in Physics Problems!!!! GAFSA Given: Ask: Formula: Solution: Answer:(must be boxed) • A passenger train travels from Boston to New York a distance of 350 km in 4 hours. What is the train’s speed? • If the car travels 400 m in 20 seconds how fast is it going? • Bart ran 5000 meters from the cops and a speed of 6 meters/second before he got caught. How long did he run? • If it takes Ashley 3 seconds to run from the batter’s box to first base at a speed of 6.5 meters per second, what is the distance she covered in that time? 2 Kinds of Speed • Average Speed • Instantaneous Speed - The total distance -the speed of an traveled divided object at one by the total instant of time. time taken. Distance Time Graph -Represents the motion of an object What is Velocity? The speed of an object and the direction of its motion is called velocity. Sec. 2 ACCELERATION - What is Acceleration? • The change in velocity divided by the time it takes for the change to happen. -happens when an object speeds up or slows down. 3 Ways to Accelerate: • SPEEDING UP • SLOWING DOWN • CHANGING DIRECTION Formula: Acceleration= final speed (m/s) – initial speed (m/s) time (s) a = sfi – si t ACCELERATION POSITIVE NEGATIVE -OBJECT SPEEDS UP -OBJECT SLOWS DOWN ZERO -SPEED DOES NOT CHANGE SPEED TIME GRAPH Acceleration Problems 1. A roller coaster car rapidly picks up a speed as it rolls down a slope. As it starts down the slope, its speed is 4 m/s . But 3 seconds later, at the bottom of the slope, its speed is 22 m/s. What is its acceleration? • 2. A cyclist accelerates from 0 m/s to 8 m/s in 3 seconds. What is his acceleration? Is this acceleration higher than that of a car which accelerates from 0 to 30 m/s in 8 seconds? SEC 3 MOMENTUM The Students will: - Explain the relationship between mass and inertia. - Define Momentum - Solve problems using the Momentum Formula Terms to Know: • Mass • Inertia • Momentum What is Mass? • The amount of matter in an object is called Mass. • Units-kilograms (kg)/grams (g), pounds (lbs) • The tendency of an object to resist change (position, movement) is called inertia. --objects with mass – inertia What is Momentum? The measure of how hard it is to stop the motion of an object is called Momentum Momentum (p) = mass (kg) x velocity (m/s) p = mv Law of Conservation of Mass: • The total momentum of the objects that collide is the same before and after the collision..