ch12 speedsection3

Motion and Force

• Chapter Twelve: Distance, Time, and Speed

• Chapter Thirteen: Forces

• Chapter Fourteen: Force and Motion

Chapter Twelve: Distance, Time, and Speed

• 12.1 Distance, Direction, and Position

• 12.2 Speed

• 12.3 Graphs of Motion

12.3 Graphs of Motion

• A position vs. time graph that is a straight line always means the object moves the same distance during each time period.

12.3 Graphs of Motion

• You can use position vs. time graphs to compare the motion of different objects.

• The steeper line on a position vs. time graph means a faster speed.

12.3 Slope• The steepness of a line is measured by

finding its slope.

• The slope of a line is the ratio of the “rise” to the “run”

12.3 Graphs of changing motion

• Objects rarely move at the same speed for a long period of time.

• A speed vs. time graph is also useful for showing the motion of an object that is speeding up

• or slowing down.

Technology Connection

Roller Coasters: The Physics Behind the Thrill

• That first roller coaster was all wood and ran in a straight line.

• Roller coasters are now made of wood or steel, and the tracks include a variety of twists and turns and loops and drops that make the ride scary and thrilling.

Investigation 12B

• How do we describe motion for which the speed is not constant?

Motion with Changing Speed