1. Mr. Dunnum Physical Science
Laws of Motion
Mr. Dunnum
Physical Science

2. Key terms Motion Speed Average Speed Instantaneous Speed Velocity
Acceleration

3. What is motion?
Motion is when an object of any sort is changing positions
Fast moving airplane
Swirling of the wind
Trickle of water

4. Distance and Displacement
Displacement includes the distance between the starting and ending points and the direction in which you travel.
This figure shows the difference between distance and displacement

5. What is speed?
Speed is the distance traveled divided by the time taken to travel the distance
Olympics runners run the 100m in 10s, which equals 10m/s or meters per second
Video

6. Practice problem
Calculate the speed of a swimmer who swims 100 m in 56s
What you know: Distance: 100m
Time: 56s
Equation: Speed= distance/time
Plug it in: Speed= (100)/(56)
Answer: Speed=1.8m/s

7. Problem
A runner completed a race of 400 m in 43.9s. In a 100m race he finishes in 10.4s. Which race was his speed faster.
100=9.6 m/s

8. Average Speed
Average speed is found by dividing the total distance traveled by the time taken
Intermediate sprinter
Never runs the race at the same speed the entire time so you will have to get an average speed.
A trip to Atlanta

9. Instantaneous Speed
When an object is in motion it changes speeds many different times
The speed of an object at one instant of time is instantaneous speed
For example a car accelerating 0-60 in 5 secs

10. Velocity/Acceleration
The velocity of an object is the speed of the object and direction of its motion
Car traveling n 60mph then turns west and continues at 60mph. Does the velocity change?
Acceleration
Means simply a change in velocity
Acceleration is more than speeding up
Acceleration is not how much velocity changes but how fast.
Video

11. Examples of acceleration/velocity
Examples of velocity
A plane taking off
Increase in speed
A car stopping at a stop sign
Decrease in speed
Jogging a winding trail
Change in direction
Driving around a corner “
Standing on the Earth’s equator
Rocket launching

12. Examples of acceleration/velocity
Examples of velocity
A plane taking off
Increase in speed
A car stopping at a stop sign
Decrease in speed
Jogging a winding trail
Change in direction
Driving around a corner “
Standing on the Earth’s equator
Rocket launching

13. Calculating acceleration
Acceleration= final velocity- starting velocity
time it takes to change velocity
A plane passes over point A with a velocity of 8000m/s north. 40 sec. later it passes over Point B at a velocity of 10,000 m/s north. What is the acceleration from A to B.
50m/s/s
Negative acceleration is also called decceleration