Motion Terms
Mechanics, Kinematics, and Average Speed
Average Speed - how much distance an object covers per unit time
Read What is Physics? and Answer These QuestionsSheldon from the Big Bang explains physics
from Alom Shaha on Vimeo.
Over-Arching Concept: If a mass speeds up, slows down or changes direction, a net Force must be present. — Newton
Video Instruction
showmethephysics.com
Enduring Understandings
1. Speed is the distance traveled per unit time.
2. Speed is measured in meters/sec.
3. A meter is about a yard.
4. Average walking speed is 1 m/s.
Unit I - Mechanics
Study of the relationship between force and motion
I. Kinematics
Mathematical methods of describing and predicting motion
Describe motion by using:
A) Average Speed
Average Speed of 120 miles per hour can also be written ... 120 miles/hr
per = divided by
Could mean travelled 120 miles in one hour, OR ... 60 miles in 1/2 hour (30 minutes), 30 miles in 15 minutes, OR 15 miles in 7.5 minutes.
100 km/hr ≈ 60 mph
Avg. Speed - how much distance an object covers per unit time
1) Units: m/s, km/hour, miles/hour
Average Speed = Δd/Δt
Distance
(meter ≈ 1 yard)
(km ≈ .6 miles)
Time
secs, minutes, hours
Ex 1
An object travels 5.0 meters in 2.0 seconds.
Find: its speed.
Ex 2
An object moves at a rate of 3.0 m/s for 1.5 seconds.
Find: how far did the object move?
Ex 3
An object moves at a rate of 4.0 m/s over a distance of 10. meters.
Find: how long did it take to travel that distance? t = ?
Check Your Understanding
5 quick questions — pick an answer to see if you’re right.
1. What does average speed measure?
2. An object travels 12 m in 4.0 s. What is its average speed?
3. An object moves at 2.0 m/s for 6.0 s. How far does it travel?
4. An object moves at 5.0 m/s over a distance of 20. m. How long does the trip take?
5. Which is closest to the average walking speed of a person?
