2. Motion, Speed & Velocity Mr. Hollander’s Science Class

3. What is Motion???  Look around…what is in motion around you?  Air particles moving  Earth circling the sun  Blood traveling in your veins  Motion is an object’s change in position relative to a reference point  Motion can be described through directions like north, south, east, west, left, up, etc.

4. Reference Points & Motion  Reference points can be nonmoving objects  Earth’s surface  Tree  Building  Reference points can be moving objects too  Two cars driving at one another  A football being thrown to a wide receiver

5. Speed…How Fast or Slow Motion Happens!!!  Speed is the distance traveled by an object divided by the time taken to travel that distance  It is related to motion because it explains how fast or slow something is moving based on the reference point used to determine motion is taking place  Speed is usually measured as meters per second (m/s)  Other measures include km/h, ft/s, and mph.

6. Average Speed  Most of the time, objects do not travel at a constant speed  Example: In a car you stop and go, obey different speed limits, traffic…  Average speed allows for a calculation to take place in order to some up the general distance and time covered through motion  Ave. Speed = Total Distance Total Time  Speed can be easily graphed as distance versus time

7. Calculating Speed  Kira jogs to a store 10 miles from her apartment. It takes her 2 hours to do so. What is her average speed?  An airplane traveling from Cincinnati to Baltimore travels 800 km in 2 hours. What is the airplane’s average speed?  Read the following problems and answer what the average speed would be for each.  Michael Phelps swims 100 meters in 50 seconds. What is his average speed?

8. Direction Matters: Velocity & Acceleration Velocity  Velocity is the speed of an object in a particular direction  It is very important that you always include a direction  Ex: Speed is 5 mph, but Velocity is 5 mph South  Constant velocity takes place in a straight line, but if speed or direction change, so does velocity Acceleration  Acceleration is the rate at which velocity changes over time  An object is said to accelerate if its speed, direction, or both change.  Positive acceleration is an increase in velocity  Negative acceleration is a decrease in velocity

9. So What is Acceleration Again?? Lets Talk About It…  Look at the following situations. Did acceleration occur and why?  A boy is riding a bike at 10 km/h. A minute later he is at 5 km/h.  You ride your bike around the block at a constant speed of 15 km/h.  You ride in a straight line at 10 km/h.

10. Summing It All Up!!!  An object is in motion if it changes position over time in relation to a reference point.  Speed is the distance traveled by an object divided by the time the object takes to travel that distance  Speed can be represented on a graph of distance versus time  Velocity is the speed in a given direction  Acceleration is the rate at which velocity changes

11. The End!!!