Terms Displacement vs. Distance Displacement: Change in position (vector) • Distance: How far an object has travelled (scalar) • Symbol: Δx or Δx • SI Unit: meter, m
Position
Terms • • Velocity vs. Speed Velocity: Rate of the change in position (vector) Speed: Rate of distance covered (scalar) Symbol: v or v SI Unit: meter per second, m/s
Average Velocity
Instantaneous Velocity
Terms • • Acceleration vs. Acceleration: The rate at which velocity changes (vector) Acceleration: The rate at which speed changes (scalar) Symbol: a or a SI Unit: meters per second or meters per second squared, m/s/s or m/s 2
Average Acceleration
Instantaneous Acceleration
Position vs. Time Graph
What are the velocities?
What are the velocities?
Average Velocity on an x-t graph
vav vs vinst on an x-t graph
x-t graph vs motion of a particle
Instantaneous Velocity on an x-t graph
Velocity vs. Time Graph • The slope of a v vs. t graph is the acceleration • The area between the curve and the horizontal axis of a v vs. t graph is the displacement
Comparison of v-t to a-t graphs
Instantaneous Acceleration vs Average Acceleration from a v-t graph
v-t graph vs motion of a particle
x-t graph vs motion of a particle with acceleration
What are the accelerations and displacements?
What are the accelerations and displacements?
Acceleration vs. Time Graph • The slope means NOTHING • The area between the curve and the horizontal axis is the change in velocity a 10 s -10 m/s/s t
Important Acceleration tells us how fast velocity changes Velocity tells us how fast position changes
Kinematics Equations (accelerated motion)
Falling Bodies, thrown up objects, and the y-direction • All things fall at the same rate (neglecting air resistance) • On earth that rate is 9. 80 m/s 2 • That rate is an acceleration • The name of that acceleration is Gravity