1. Unit 1: Intro to Physics
Speed & Velocity

2. when something occurs (an event)
I. Time t is___________________________________
It is a _____________________________
scalar
In physics, the time between two ___________ is
is called the ___________________________ .
The basic unit for time is the second, s .
****Other units, such as minutes, hours
must usually be converted into seconds
before solving any problems.
events
time interval

3. speed v = ______________________
=____________________________________
=_____________________________________
how fast an object moves
time rate of change in distance
a scalar (no dir., only mag.)
Ex: v = 55 mph
mag.
Speed v can be ______________ (not changing), or
it can change. If it changes, the speed at any
instant is called the ____________________ speed.
The ______________speed, vavg = v is:
constant
instantaneous
average
Equation for v from PRT
(Physics Reference Tables): v
= d/t

4. Ex: Jenny runs 95 meters in 15 seconds.
Find her average speed. Show all work.

5. Ex. A car, initially moving at a speed of 25 m/s,
increases its speed to 45 m/s in 3.0 seconds. What is its average speed during the 3.0 s?
initial
vi = ____________ speed =
25 m/s
vf = ____________ speed =
final
45 m/s
 This equation is NOT
in your PRT. You must
_____________________ .
v = (vi + vf) 2
memorize it
v =
(25 m/s + 45 m/s)
= 35 m/s 2

6. How far will the car in the last example
travel in 12 seconds?
Given:
Unknown:
Word problem hints:
1. If an object starts from rest: vi =
2. If an object comes to rest: vf =
3. If the speed of an object does NOT change,
v =
vi =
vf = v

7. III. velocity v = _________________________________
time rate of change in displacement
displacement =
time
= ________________________________ __________________________________
a vector with the same
dir. as the displacement
Ex:
v = 55 mph, north
dir.
mag. of the velocity = the ____________
speed
velocity = ___________ + ________________
speed
direction
Draw velocity as an _________:
arrow
55 mph

8. ******Speed and velocity have same _________
and use the same_______________:
units
equation
average velocity:
Ex: A car travels 4.40 x 102 meters east in
8.0 hr. Find the car’s velocity.

9. Ex: Mr. McKeever walks 1) 6.0 m east in 4.0 s,
then runs 2) 2.0 m west in 0.50 s. Find his
average speed in each part, and 3) the average
speed over the entire time. 1) v
= d/t
= 6.0 m
4.0 s
= 1.5 m/s
= 2.0 m
0.5 s 2) v
= d/t
= 4.0 m/s
= 8.0 m
4.5 s 3) v
= d/t
= 1.7m/s
d = the _____________ distance
total
Why is the average speed over the entire time
closer to the answer for part _____ ? 1)

10. IV. Uniform motion:
constant ________________
velocity
Uniform
motion
or….
constant ______________
in______________________
speed
1 direction
Ex. A car leaks oil at a constant rate while
moving to the right in uniform motion. Sketch
the pattern of drops it leaves behind.