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Motion, Forces, and Energy Chapter 1 Motion Section 1 Describing and Measuring Motion. Key Concepts: When is an object in motion? How do you know an object’s speed and velocity? How can you graph motion?. Key Terms: Motion Reference Point International System of Units Meter.
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Motion, Forces, and Energy Chapter 1Motion Section 1Describing and Measuring Motion Key Concepts: When is an object in motion? How do you know an object’s speed and velocity? How can you graph motion? • Key Terms: • Motion • Reference Point • International System • of Units • Meter • Speed • Average Speed • Instantaneous Speed • Velocity • Slope
Objects in Motion • Motion- The state in which one object’s distance from another is moving • Reference Point- A stationary place or object used for comparison to determine if something is in motion. • Trees • Signs • Buildings • The object is in motion if it changes position relative to a reference point.
Objects in Motion • Relative Motion • Depending on your reference point you may or may not be moving • Sun= Moving…FAST! • Table= Not Moving
Objects in Motion • International System of Units (SI)- The system of measurement based on multiples of ten (10) and on established measures of mass, length, and time used by scientist across the world • Meter (m)- Length • A little longer than one (1) yard • Objects smaller than 1 m are measured in centimeters (cm) • 100 cm = 1 m • Objects smaller than 1 cm are measured in millimeters (mm) • 1000 mm = 1 m • Objects bigger than 1 m are measured in kilometers (km) • 1 km = 1000 m
Speed and Velocity of Motion • Speed- The distance the object travels per unit of time. • Need to know: • The distance the object traveled • The amount of time it traveled for • Speed Equation: • Speed= Distance / Time • Average Speed- Overall rate of speed at which an object moves • Instantaneous Speed- The rate at which an object is moving at a given instant in time
Speed and Velocity of Motion • Velocity- Speed in a given direction • Need to know: • The speed of the object • The direction of the object • Need both speed and velocity to fully describe the object’s motion • Where hurricanes are going • Airplanes
Graphing Motion • You can use a line graph in which you plot distance vs. time • Time is the horizontal/x axis • Distance is vertical/ y axis • A point on the graph is the distance an object has traveled at that particular time
Graphing Motion • Slope- The steepness of a line on a graph • Tells how fast one variable changes in relation to the other variable • Rate of Change • Steeper the slope = Greater the speed
Graphing Motion • Calculating Slope • Divide Rise over Run • Rise = Vertical difference between any two points on the line • Run= Horizontal difference between the same two points • Different Slopes • Most objects do not move at a constant pace • Different slopes on the same graph can tell you which was faster, slower, or having no movement
Chapter 1Motion Section 1Describing and Measuring Motion When is an object in motion? How do you know an object’s speed and velocity? How can you graph motion? Section Review on p. 15