Motion

Frame of Reference A place or object used for comparison to determine if an object is in motion. A place or object used for comparison to determine if an object is in motion. Objects that we call stationary—such as a tree, a sign, or a building—make good reference points. Objects that we call stationary—such as a tree, a sign, or a building—make good reference points.

Change in Motion An object is in motion if its distance from another object is changing. An object is in motion if its distance from another object is changing. Theory of Plate tectonics- Earth’s landmasses have changed position over time because they are part of plates that are slowly moving. Theory of Plate tectonics- Earth’s landmasses have changed position over time because they are part of plates that are slowly moving.

Speed The speed of an object is the distance the object travels per unit of time. The speed of an object is the distance the object travels per unit of time. AVERAGE SPEED- The overall rate of speed at which an object moves; calculated by dividing the total distance (measured in meters) an object travels by the total time. AVERAGE SPEED- The overall rate of speed at which an object moves; calculated by dividing the total distance (measured in meters) an object travels by the total time. INSTANTANEOUS SPEED-The speed of an object at one instant of time. INSTANTANEOUS SPEED-The speed of an object at one instant of time. Speed= Distance /Time

Velocity Speed in a given direction Speed in a given direction When you know both the speed and direction of an object’s motion, you know the velocity of the object. When you know both the speed and direction of an object’s motion, you know the velocity of the object. Velocity= distance/time

Graphing Motion You can show the motion of an object on a line graph in which you plot distance versus time. You can show the motion of an object on a line graph in which you plot distance versus time. The steepness of a line on a graph is called slope. The steepness of a line on a graph is called slope.Rise/run Distance Time Graph Distance Time Graph

Acceleration The rate at which velocity changes The rate at which velocity changes In science, acceleration refers to increasing speed, decreasing speed, or changing direction. In science, acceleration refers to increasing speed, decreasing speed, or changing direction. To determine the acceleration of an object moving in a straight line, you must calculate the change in speed per unit of time. To determine the acceleration of an object moving in a straight line, you must calculate the change in speed per unit of time.

Acceleration Acceleration= final speed-initial speed/time To increase acceleration you must decrease mass To increase acceleration you must decrease mass An increase in mass would decrease acceleration An increase in mass would decrease acceleration