1. aav t v = aav = average acceleration; v = change in velocity;
The average acceleration of an object is defined
to be the ratio of its change in velocity to the
time taken to change the velocity. v
aav = t
aav = average acceleration;
in units of m/s/s, mph/s, ft/s/s, km/hr/s, etc...
v = change in velocity;
in units of m/s, in/s, ft/s, km/hr, mph, etc...
t = change in time;
in units of s, min, hr, etc...

2. The “sign” of the acceleration indicates whether the velocity is
increasing or decreasing.
A positive sign = increasing velocity
It will also be an increase in
speed if the object is traveling in the positive
direction. It is a decrease in speed otherwise.
A negative sign = decreasing velocity
It will also be a decrease in
speed if the object is traveling in the positive
direction. It is an increase in speed otherwise.

3. A car traveling at 60 mph accelerates to
90 mph in 3 seconds. What is the
car’s acceleration?
Velocity(final) - Velocity(original)
Acceleration =
time
90 mph - 60 mph =
3 seconds
30 mph =
3 seconds =
10 mph/second

4. Positive acceleration Negative acceleration

5. A car traveling at 60 mph slams on the breaks to
avoid hitting a deer. The car comes to a safe stop
6 seconds after applying the breaks. What is the
car’s acceleration?
Velocity(final) - Velocity(original)
Acceleration =
time
0 mph - 60 mph =
6 seconds
- 60 mph =
6 seconds =
- 10 miles per hour per second

6. Velocity & Acceleration Sign Chart+ -
Moving in positive direction; Speeding up
Moving in negative direction; Slowing down
Moving in positive direction; Slowing down
Moving in negative direction; Speeding up

7. Negative Acceleration, Increasing Speed
Initial velocity = -5 m/s
Final velocity = -10 m/s
time= 25 s
acceleration = ?

8. Drawing Velocity Vectors
When following the path of an object, the velocity vector is always in the direction of motion.

9. Drawing Acceleration Vectors
Yes, acceleration is also a vector quantity. (YAY!- *rolls eyes*)
If object is speeding up, then acceleration vector is in the same direction as the motion.
If object is slowing down, then acceleration vector is in the opposite direction of motion.