Describing Motion Part 1 Position Distance and Displacement

Describing Motion Part 1 – Position, Distance and Displacement

Kinematics • The study of motion

What types of motion are there? • What words do you associate with motion? • Before we can start describing motion, what is the most important place to start?

Position • What is your position? • Position (d) – the location of an object with respect to a reference point

Describe your position in the classroom • What should our reference point be?

Changing Position Start Position 1 Finish Position 2 Reference Point

What else can we describe here? Start Position 1 Finish Position 2 Reference Point

How to describe changing position? • Displacement (Δd) ▫ A change in position of an object ▫ The difference between the initial position and the final position

Changing Position Start Displacement - From start to finish Position 1 Finish Position 2 Reference Point

How to describe changing position? • Distance (d) ▫ The length of the path you travel to get from position 1 to position 2

Changing Position Start Distance – length of path travelled Displacement Direct line from start to finish Position 1 Finish Position 2 Reference Point

The Difference • Displacement ▫ Think spy satellite photos ▫ What happened? • Distance ▫ Think spy satellite video monitoring ▫ How did it happen?

Example # 1: Mohammed runs twice around a 400 m track. • What distance did he cover? • What is his displacement?

Example # 2 • A cat walks 4. 0 m [E], then 9. 0 m [W], then 2. 0 m [E]. What is the cat’s distance and displacement? • Gurganjot moves 1. 0 m[N] then 3. 0 m[S] then 12. 0 m [S] then 18 m[N]. What is Gurganjot’s distance and displacement?

Example # 3 • A cat walks 2. 5 m[N] then 4. 0 m [W] then 6. 0 m [S]. What is the cat’s resultant displacement? • Mr. Simnett runs 10 m[S] then 14 m [E] then 2. 0 m [S]. What is his resultant displacement?

Example # 4 • A snowboarder travels 300 m [S] then 175 m [20 E of S]. What is the snowboarder’s resultant displacement? • A boat cruises around a lake to take in the sights. The boat goes 2. 7 km[W] then 8. 5 km [22 S of W]. What is the boat’s resultant displacement?

Example # 5 • A person strolls around the mall walking 20 m [E], 14 m[15 S of E] then 32 m [S]. What is the person’s resultant displacement? • A shark swims 400 m [E] then 1200 m[S] then another 800 m [25 S of W] before it finds it’s prey. What is it’s resultant displacement?