Transcript Section 1.2 Outline Speed measures how fast position changes I. Position can change at different rates 1) speed: a measure of how fast something moves a)

Section 1.2 Outline
Speed measures how fast position changes
I.
Position can change at different
rates
1) speed: a measure of how fast something
moves
a) rate at which distance changes compared to
time
b) a measurement; can be fast or slow
2) speed and position are related by time –
speed measures how quickly position
change
A. Calculating Speed
1) objects that travel at different speeds
move different distances in the same
amount of time
2) S = d/t (S = speed, d = distance,
t = time)
B. Average Speed
1) speed is not constant; it is always
changing
2) moment-to-moment speed
(instantaneous) is difficult to measure
3) easiest to calculate average speed
over a distance
C. Distance-Time Graphs
1) shows how speed relates to distance
and time
2) shows how both distance and speed
change with time
3) a flat, or horizontal, line shows a
speed of 0 m/s
4) time is on horizontal, or x-axis and
distance is on vertical, or y-axis
II. Velocity includes speed
and direction
1) velocity: a speed in a specific direction
2) example: 3 m/s south
A. Velocity
1) to calculate, need both speed and
direction
2) vector: a quantity that has both size
and direction
3) represented by an arrow (size and
direction)
B. Velocity versus speed
1) two objects may have same speed,
but different velocities
2) average speed depends on total
distance traveled
3) average velocity depends on total
distance from starting point