1. Three featured concepts are: Speed Velocity Acceleration
MOTION
Three featured concepts are:
Speed
Velocity
Acceleration

2. MATH CONNECTION These are called rates
The units in Math may have been BE
Like Feet per second; Miles per hour
Ft./Sec OR mi./hr. or mph

3. In Science we use SI UNITS
Meters per second; kilometers per hour
m/s OR km/h or kph
There are as may rates as there are units:
cm/s; mm/h; even mm/y or cm/century
It all depends on the topic of study.

4. What’s the dif? Glad you asked:
Speed is a rate of distance over time or just called magnitude like:
5 m/s or 25 mph.
VOLOCITY is the rate of distance over time but indicates a direction! Magnitude + direction:
5m/s -north or 25 mph-south

5. So can you tell the difference?
TRY SOME:
15 m/s
100 mph - north
2.34 cm/s
17.4 ft./hr.-up
25 kph- south
11.67 km/h

6. How about Acceleration?
Acceleration is defined as a change in speed of velocity over time. More complicated for sure.
a =∆v / ∆t
We have to check out the white board to see this broken down!!!!

7. UNITS for ACCELERATION
Because it involves a double division the units of course are complicated usinfg two speeds together.
Examples of acceleration units are:
m/s/s (not new) remember 9.8 m/s/s? or m/s2
Ft./sec./sec or ft./sec.2
Km/h/s
m/h/s
Basically any distance divided by a time divided by another time:
any
d/t/t defines an acceleration unit of measure!

8. Sample Speed Problem #1
It takes a car 30 seconds to go 90 meters. What is the speed?
Menu: V = d/t (means d ÷ t)
V= ? = 90m/ 30s
d = 90 m V = 3m/s
t = 30 s

9. PROBLEM # 2
A car can travel a speed of 3 m/s over a time of 30 seconds how far would it go?
Menu: d = vt (means v X t)
d = ? = (3 m/s) (30 s) (cross cancel s)
v = 3 m/s d = 90 m
t = 30 s

10. PROBLEM # 3
How long will it take a car to go 90 meters at a speed of 3 m/s?
Menu: t = d/v ( means d ÷ v )
t = ? = 90 m / 3m/s
d = 90 m [t= 30 s]
v = 3 m/s

11. ACCELERATION Sample Problem:
A car’s speedometer indicates a speed of 30 kph and after 10 seconds of time the driver notices the speed is now 90 kph.
What is the car’s acceleration?
a = ? a = vf - vi t
vf = 90 km/h = 90 km/h - 30 km/h
10 s
vi = 30 km/h = km/h
t= 10 s a = 6 km/h/s

12. Deceleration a= ? a = Vf - Vi t Vf = 55 kph = 55 kph – 75 kph 5s
Sample Problem:
A truck is going 75 kph and 5 seconds later it is clocked going 55 kph. What is the deceleration.
HINT: Use the same equation (formula) then change the a to (–a) after finding the answer.
a= ? a = Vf - Vi t
Vf = 55 kph = 55 kph – 75 kph 5s
Vi = 75 kph = kph
t = 5s a = -4kph/s
-a = 4 kph/s