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Forces and Energy. Chapter 1: MOTION. Section 1 - Describing Motion. When is an object in motion? An object is in motion if it changes position relative to a reference point. See Page 5, Figure 1. What should you use as your frame of reference?. Relative Motion. Page 6 - Apply It.
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Forces and Energy Chapter 1: MOTION
Section 1 - Describing Motion When is an object in motion? An object is in motion if it changes position relative to a reference point.
See Page 5, Figure 1 What should you use as your frame of reference?
Relative Motion Page 6 - Apply It
Section 2: Speed and Velocity Speed -the distance an object moves per unit of time
Average Speed vs. Instantaneous Speed Average Speed • Total Distance Total Time Instantaneous Speed • Speed at which an object is moving at a given instant in time The speedometer in a car gives the car’s _____________________ speed.
3 km / .8h = 3.75 km/h 50km / 3h = 16.7 km/h 50 km / 2.5h = 20 km/h 3 km / 1h = 3 km/h 3 km + 50 km + 12 km = 65 km .8 h + 3 h+ 1.2 h = 5 h 65 km / 5 h= 13 km/h 1 h+ 2.5 h + 1 h = 4.5 hrs Use the data from all three legs to solve for each athlete’s average speed. 65 km/ 4.5 h = 14.4 km/h
What is Velocity? Speed in a given direction. An error in determining a velocity, either in speed or in direction, could lead to a collision.
How do you describe the motion of an object? See pg 13; Figure 3 What are the three parts to describe motion? - distance the object travels - objects average speed - the direction the object is traveling.
The motion of an object can be shown on a line graph in whichdistance vs. timeis plotted. -The steepness of a line on a graph is called slope. - Slope is the rate of change.
Graphing motion continued... To calculate slope: Slope = Rise (the vertical difference) Run (the horizontal difference)
What is the Jogger’s Speed? Runner at a constant speed of 100 m/min Rise = 1200 - 800 Run = 6 - 4
What happens when objects don’t travel at a constant speed? Jogger is at rest... 0 m 1 min Jogger ran fastest… 0 m/min Rise Run 1000-800= 200m 300-150 = 150m 9-8 = 1 min Rise 200/1 = 200m/min 2 - 1= 1 min Run 150/1 = 150 m/min
Assessing Understanding: Is it possible for a distance-vs.-time graph to be a vertical line?