Position, Speed, and Direction

Students are introduced to multiplying a negative number with a positive number, using the context of velocity, time, and position. They practice using signed numbers to represent the position of an object along a line relative to a reference position. Students see that signed numbers can also be used to represent speed with direction. Scientists use the term velocity to describe the speed of an object in a specified direction. If one object is moving with a positive velocity, then any object moving in the opposite direction will have a negative velocity. Students use several examples in the context of moving along a line to see that the product of a negative velocity and a positive travel time results in a negative position relative to the starting point.

Grade 7, Episode 12: Unit 5, Lesson 8 | Illustrative Math