MOTION – Chapter 2- section 1 Think of a time you went to an amusement park. Describe three rides and how they caused you to move.

A reference point is needed to determine the position of an object. Motion occurs when an object changes its position relative to a reference point. Frame of reference- a coordinate system in which the position of the object is measured. The x-axis and y-axis are drawn so that they intersect the reference point

Distance- An important part of describing the motion of an object to describe how far it has moved. Displacement- The distance and direction of an objects change in position from the starting point. HOW DO DISTANCE AND DISPLACEMENT DIFFER? Distance describes how far an object has moved; Displacement includes distance and direction of an object’s change in position from its starting point.

SPEED -The distance an object travels per unit of time. Calculating speed- Speed ( In meters/seconds)= Distance/time s=d/t 1.If a motorcyclist travels 20 km/h to a friends home 5 km away, how long will the trip take? 2. A car traveling a constant speed covers a distance of 750m in 25s. What’s the cars speed?

Motion with a constant speed- If an item travels in a speed that does not slow dow, nor speed up. For example: A car traveling on a highway Changing speed: intervals of speeding up and slowing down. For example-A car at a stop sign. Average speed- The total distance traveled divided by the total time of travel. Instantaneous speed- the speed at a given point in time Changing instantaneous speed- the speed is different at every point in time.

Graphing motion Time is always plotted on the horizontal ais of the graph. Distance traveled is plotted on the vertical axis of the graph. Thje slope of a line plotted on a distance- time graph is the speed.

Velocity - includes the speed of an object and the direction of its motion. * For an object to have constant velocity, speed and direction must not be changing. HOW ARE SPEED AND VELOCITY DIFFERENT? Velocity includes direction; speed does not

Motion of the earths crust Geological evidence has shown that the Earth’s continents have moved slowly over time. Pangea began to separate into smaller pieces. The continents are still moving today! The Earth’s crust moves over putty like interior

ACCELERATION Acceleration is the rate of change of velocity. When the velocity of an object changes, the object is accelerating. -If the speed of a car is increasing the car has positive acceleration. -If the speed of a car is decreasing the car has negative acceleration. *** Anytime a moving object changes direction, its velocity changes and it is accelerating.

Calculating acceleration change in velocity= final velocity- initial velocity = vf-vi Acceleration equation Change in velocity(in meters/seconds) Time( in seconds) a= vf-vi t

Motion and Force A force is a push or pull on an object NET FORCE- the combination of all forces acting on an object When all forces are balanced, the net force of an object is zero Unbalanced forces cause the motion of forces to change

INERTIA AND MASS Inertia- the tendency of an objet to resist any change in its motion. An object will keep moving at the same speed, in the same direction unless an unbalanced force acts upon it. The larger the object, the greater its inertia Sir Issac Newton- British scientist who studied the motion of objects.

Newton’s first law of motion This law states that an object moving at a constant velocity keeps moving at that velocity unless an unbalanced force acts upon it. If an object is at rest, it stays at rest unless an unbalance net force acts upon it. In a car crash, inertia causes an unrestrained passenger to continue moving at the speed of the car before the crash.