1. MOTION
• We now know that unbalanced
forces can change motion

2. Recognizing Motion
Textbook pg 17-18
• When is an object in motion?
• Are you or your book moving
– Compared to the floor?
– Compared to the sun?
• What is a reference point?
• What do we assume about a reference point?
• For the bus example, why do you think you
are moving backward?

3. Recognizing Motion ANSWERS
Textbook pg 17-18
• When is an object in motion?
• When it’s distance from another object is changing
• Are you or your book moving?
– Compared to the floor? NO
– Compared to the sun? YES
• What is a reference point?
• A place or object used for comparison
• What do we assume about a reference point?
• It is stationary

4. Recognizing Motion ANSWERS
Textbook pg 17-18
• For the bus example, why do you think you are
moving backward?
–Your reference point (the other bus) wasn’t
stationary
You 
Reference 
point

5. What’s a Frame
of Reference?

6. BACKGROUND
OR OBJECT
USED FOR
COMPARISON

7. NOW WE ARE GOING TO LOOK AT WAYS TO
DESCRIBE AND MEASURE MOTION
SPEED

8. HOW DO WE DESCRIBE SPEED?
HOW FAST SOMETHING GOES

9. How do we CALCULATE SPEED?
• How we describe the speed of a CAR:
– Miles per hour (MPH)
OR
– Kilometers per hour (km/h)
• What does the miles or kilometers measure?
– They are units for distance
• What does the hour measure?
– It is a unit for time
• What does the “per” or “/” mean in math?
– division

10. SPEED =RATE that an
object moves
Distance (D)
Rate (speed) =
Time (T)

11. DISTANCE
Length between two places
Distance = rate (speed) x time
D= RT
“Dirt”

12. TIME
=
d
r (speed)T

13. STEPS IN PROBLEM
SOLVING
 STEP 1. Write the formula
 STEP 2. Substitute given
numbers and units
 STEP 3. Solve for the
unknown.

14. SAMPLE PROBLEM:
At what speed did a
plane fly if it
traveled 1760
meters in 8 seconds?

15. SOLUTION
Step 1. Question asked “What
speed” so use:
Rate (Speed) = Distance/Time

16. SOLUTION
Step 2. substitute distance = 1760 meters
substitute time = 8 seconds
Speed = 1760 meters/ 8 seconds

17. SOLUTION
Step 3. Do the math to get your answer
Speed = 220 meters/second
(m/sec)

18. SAMPLE PROBLEMS:
1. A car travels 240 kilometers
in 3 hours. What is the speed
of the car during that time?
ANSWER: S= d/t S= 240 km/3 hr
80 KM/HR

19. The speed of a cruise ship is 50
km/hr. How far will the ship
travel in 14 hours?
Answer: D = ST
700 km