Upload
tiffany-melton
View
220
Download
0
Tags:
Embed Size (px)
Citation preview
Motion
Objectives
• Define motion.
• Calculate the speed of a moving object.
• Distinguish between velocity and acceleration.
Begin
• How do you feel when you are standing on a stopped bus and then the bus begins to move? Why?
Motion
• The change in position of an object as compared with a reference point.
Reference Point
• A location to which you compare to other locations
Question
• Car A is going 45 mph in the left lane. Car B is going 45 mph in the right lane directly along side car A. Is car B in motion relative to car A? Explain.
Relative Motion
• http://www.classzone.com/books/ml_science_share/vis_sim/mfm05_pg7_relmotion/mfm05_pg7_relmotion.html
Not All Motion Is the Same
• All motion is not the same.
Activity• Differentiate between the
motion of a baseball and a jet.
Distance
• The length of the actual path traveled by an object.
• A car travels 50 km.
• A baseball travels 60 feet and 6 inches.
Activity
• Restate the definition of distance in your own words and give an example of distance. Write your answer in your notes.
Speed• The distance an object travels
in a given amount of time.
• A car travels 50 km in one hour.
• A baseball travels 85 miles per hour.
Calculating Speed
• The formula R=D/T is used to calculate speed.
• R is speed (or rate), d is distance, and t is time.
Activity
• If a runner runs 100 meters in 50 seconds, what is his speed in meters per second?
• How far could this runner run in 40 seconds?
Velocity
• Speed in a definite directiondefinite direction.
• 65 km/hour describes speed.
• 65 km/hour north describes velocity.
Velocity
• Two objects can have the same speed but have different velocities.
• 70 mph north and 70 mph south.
Acceleration
• Acceleration is a change in velocity in a period of time.
Which of the Following Are Examples of Acceleration?
• A car stops at a stop light.
• A car goes from 0 to 45 mph.
• A car races around an oval track at a constant speed.
Acceleration
• Acceleration is any change (speed or direction) in an objects motion.
• Acceleration can be negative.
Acceleration of Objects in Free Fall
• The acceleration of an object in free fall on earth is 9.8 m/s2.
• This means that in each second the speed of the object will increase by 9.8 m/s2.
Calculating Acceleration
• Use the following formula:
A= Vfinal-Vinitial
________________
tA= acceleration
V= velocity
T= time
Calculating Acceleration
• John starts sliding with a velocity of 1 m/s. After 3 s, his velocity is 7 m/s. What is John’s acceleration?
Review
• What is the difference between speed and velocity?
• A train travels 85 km in 1.5 hours. What is the speed of the train?
Review
• What is the difference between velocity and acceleration?
• If the moon travels at a constant speed around the earth, would the moon’s velocity also be constant? Why?