CALCULATING SPEEDSpeed = Distance traveled Or s = d Time elapsed t • Example: If a runner travels 100 m in 10 seconds what was his average speed? • So, what are the units for speed? • How would you re-arrange this formula to solve for… • Distance? • Time?
CONSTANT SPEED• A moving object that doesn’t change it’s speed travels at constant speed• Constant speed means equal distances are covered in an equal amount of time
WHAT TIME KNOW FOR TEST ON FRIDAY• Measurements: how to read a measurement scale, SI/english units • SI Units: Must know conversion factors from kilo- to milli- • Know how to convert numbers between unit prefixes• Precision & accuracy: how to determine if data is precise or accurate• Significant figures: Determining the number of significant figures in a given number, determining sig figs in math operations• Scientific notation: converting from standard form to scientific notation, scientific notation to standard form, and math operations for scientific notation• Factor label method: converting units• Speed: using the speed equation, graphing speed, converting between speed units• Algebra of physics: rearranging equations to solve for a variable.
WHAT TIME KNOW FOR TEST ON FRIDAY• What to do: • Review and re-do homework problems • Review labs we have done in class • Re-read class and textbook notes • See powerpoints from class on website • Review vocab for this unit
EXAMPLE: CONVERSIONS• Convert 3.00x10 8 m/s (the speed of light) to mph
ALGEBRA OF PHYSICS• In physics, we will be re-arranging a number of equations in order to isolate a variable on one side of the equation to solve for an unknown. Let’s freshen up on these skills!• Rearrange the following equations to solve for x: a = 3x + b ½ x2 +3 = y 5(x + y) = z ½h=j+½x