Chapter 2 Motion in one Dimension Mrs. Schwartz 2016
Objectives Describe motion in terms of frame of reference, displacement, time, and velocity. Calculate the displacement of an object traveling at a known velocity for a specific time interval. Construct and interpret graphs of position versus time.
One Dimensional Motion To measure motion, you must choose a frame of reference. A frame of reference is a system for specifying the precise location of objects in space and time.
Displacement Displacement is a change in position. Displacement is not always equal to the distance traveled. The SI unit of displacement is the meter, m.
displacement = final position – initial position x = xf – xi displacement = final position – initial position Δx
Average Velocity Average velocity is the total displacement divided by the time interval during which the displacement occurred.
Sample problem During a race on level ground, Andrea runs an average velocity of 6.02 m/s to the east. What is Andrea’s displacement after 137s ? List givens. List unknown List equation Plug in Solve
Heather and matt walk with an average velocity of 0. 98m/s eastward Heather and matt walk with an average velocity of 0.98m/s eastward. If it takes them34 min to walk to the store, what was their displacement? If Joe rides his bike in a straight line for 15 min with an average velocity of 12.5 km/h south, how far has he ridden? It takes you 9. min to walk with an average velocity of 1.2 m/s to the north from the bus stop to the museum entrance. What is your displacement. Simpson drives his car with an average velocity of 48.0 km/h to the east. How long will it take him to drive 144km on a straight highway?
Velocity and speed Velocity describes motion with both a direction and a numerical value (a magnitude). Speed has no direction, only magnitude. Average speed is equal to the total distance traveled divided by the time interval
Speed Average speed = Distance traveled Time of travel
Velocity and graphs Can also be determined by the slope of a position-time graph Slope = rise/run
Instantaneous vs average Velocity at some instant. Not the same as average!