Velocity-Time Graphs

What is it and how do I read one?

Graphing Acceleration:Speed vs. Time Graphs

0

2

4

6

8

10

12

14

0 1 2 3 4 5 6

Time (s)

Sp

ee

d (

m/s

)

Speed is increasing with time = accelerating

Velocity-Time Graphs

1) Line is straight = constant velocity, zero acceleration

time (s)

velo

city

(m

/s)

N

S

Object is moving at a constant velocity North.

Velocity-Time Graphs

A horizontal line on the V-T graph means constant velocity.

time (s)

velo

city

(m

/s)

N

S

Object is moving at a constant velocity South.

Velocity-Time Graphs

If an object isn’t moving, its velocity is zero.

time (s)

velo

city

(m

/s)

N

S

Object is at rest

Graphing Acceleration:Speed vs. Time Graphs

0

2

4

6

8

10

12

14

0 1 2 3 4 5 6

Time (s)

Sp

ee

d (

m/s

)

1)In Speed vs. Time graphs:Acceleration = Rise/Run = 4 m/s ÷ 2 s = 2 m/s2

Run = 2 s

Rise = 4 m/s

Velocity-Time Graphs

V-T graph has positive slope.

time (s)

velo

city

(m

/s)

N

S

Positive velocity and positive acceleration: object is speeding up!

time (s)

velo

city

(m

/s)

N

S Negative velocity and positive acceleration: object is slowing down.

Velocity-Time Graphs

V-T graph has negative slope.

time (s)

velo

city

(m

/s)

N

S

Positive velocity and negative acceleration: object is slowing down,

time (s)

velo

city

(m

/s)

N

SNegative velocity and negative acceleration: object is speeding up! (in negative direction)