Do Now warm-up prompt

Average Speed - how much distance an object covers per unit time

Read What is Physics? and Answer These Questions

Sheldon from the Big Bang explains physics

Why is Science Important?

from Alom Shaha on Vimeo.

“The most incomprehensible thing about the universe is that it is comprehensible.”

— Einstein

Over-Arching Concept: If a mass speeds up, slows down or changes direction, a net Force must be present. — Newton

Video Instruction

showmethephysics.com

Fill in the Blank Notes

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

Boy running with a soccer ball

I. Kinematics

Mathematical methods of describing and predicting motion

Top view of a woman walking

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.

Speedometer gauge
Can you believe the speed limit in Calgary, Canada is 100!!
Canadian speed limit sign showing 100 km/h

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 stick

(meter ≈ 1 yard)

(km ≈ .6 miles)

Time

Stopwatch

secs, minutes, hours

Ex 1

Given

An object travels 5.0 meters in 2.0 seconds.
Find: its speed.

Speed = Δd/Δt = 5.0 m / 2.0 sec

= 2.5 m/s

Ex 2

Given

An object moves at a rate of 3.0 m/s for 1.5 seconds.
Find: how far did the object move?

Speed = Δd/Δt → 3.0 m/s = Δd / 1.5 sec

Δd = 4.5 m

Motion map for 3.0 m/s over 1.5 seconds
Motion Map — 3.0 m/s for 1.5 seconds, Δd = 4.5 m
Motion map diagram
Muybridge animated race horse
Photos made by Eadweard Muybridge (1830-1904). Animation by User Waugsberg. Public Domain.

Ex 3

Given

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 = ?

Speed = d/t → 4.0 m/s = 10. m/t (Cross Multiply)

(4.0 m/s)t = 10. m (Divide by 4)

t = 2.5 seconds

Motion map for 10 meters at 4 m/s
Motion Map — How much time to travel 10 m @ 4 m/s? t = 2.5 seconds