150 likes | 652 Views
Speed, Velocity, and Acceleration. “I Feel the Need, the Need for Speed!”. Speed. Speed, velocity, and acceleration describe how an object’s position and motion change through time. Rates measure change in something over a length of time. Speed is the rate of change of distance over time.
E N D
Speed, Velocity, and Acceleration “I Feel the Need, the Need for Speed!”
Speed • Speed, velocity, and acceleration describe how an object’s position and motion change through time. • Rates measure change in something over a length of time. • Speed is the rate of change of distance over time.
Constant Speed • An object moving at constant speed travels the same distance each second. • This hurdler is moving at a constant speed of 5m/second.
Changing Speed • A car driving in town must slow down and speed up, therefore its speed is not constant. • The car’s speed at any given time is called its instantaneous speed. • An object moving at a constant speed has the same instantaneous speed at all times.
Average Speed • Average speed is the total distance traveled divided by the total time. If you know any 2 of the variables, you can calculate the missing variable. What is the relationship between distance, average speed, and time?
Velocity • Velocity is the speed and direction of a moving object. • Speed is the rate of change of distance with time. • Velocity is a vector because it has both direction and size. • The size of a velocity vector is the speed.
Acceleration • Acceleration is the rate at which velocity changes with time. (Which of these graphs shows positive acceleration? Which shows negative acceleration?) Acceleration
Acceleration (cont’d) • The horses on the carousel are moving at a constant speed, but changing direction, so they are constantly changing velocity and, therefore, accelerating.
Lesson 1-2: Review Acceleration is the rate of change of ____. A velocity B speed C time D direction
Lesson 1-2: Review A car stopping at a red light is and example of a(n) ____. A displacement B acceleration C direction D velocity
Lesson 1-2: Review It takes a runner 42.1 s to run a distance of 150 m. What is the runner’s average speed? A 0.28 m/s B 3.56 m/s C1.75 m/s D6.31 m/s