PHYSICS DISTANCE AND DISPLACEMENT

Introduction

• Kinematics is the study of an object’s motion in terms of its displacement, distance traveled, velocity and acceleration.

Definition

• • A vector is a quantity that includes both direction and magnitude A scalar does not involve direction, only

magnitude

Very Important Video

Example

• Which of the following are vectors which are scalars?

55 mph 55 mph North 18 ft 18 ft left

Position

• • • • Everything exists somewhere in the universe.

To describe the position that object is located you need a reference point.

We can arbitrarily choose that point and call it the

origin

The laws of physics work no matter where you place the origin, choose what is simple.

Distance

• • Distance is a scalar quantity that refers to "how much ground an object has covered" during its motion.

Measured in meters

Displacement

• • • • Displacement is a vector quantity that refers to "how far out of place an object is“ Displacement is an objects change in position.

Change in means the difference between the initial position and the final position Measured in meters

What’s the Difference?

Notation

• • • ∆𝐝 is what we call the displacement vector ∆𝒙 is what we call the displacement vector if it is purely horizontal ∆ y is what we call the displacement vector if it is purely vertical

Example 1

A rock is thrown straight up ward from the edge of a 30m cliff, rising 10m the falling all the way down to the base of the cliff. Find the rock’s displacement. Find the rock’s distance traveled.

Example 2

An infant crawls 5m East then 3m west, then 1m East. Find the infant’s distance and displacement.

Example 3

In a track and field event an athlete runs exactly once around an oval track, a total distance of 500 m. Find the runners displacement for the race.