1. Kinematics Intro

2. Objects and Systems Classical physics studies how objects behave under different conditions An object is a piece of matter to which some sort of action (push or pull) is directed A system is any group of one or more objects we choose to study What are the parts of this system?

3. Mechanics Branch of physics that studies motion Two parts Kinematics – describes motion Dynamics – tells why motion occurs

4. Kinematics Translational Motion – motion without rotation All measurements must be made with respect to a frame of reference A man walks at 5 km/hr toward the front of a train traveling at 80 km/hr. What is the speed with respect to a) another passenger on the train b) a person standing outside the train? Unless otherwise stated the frame of reference is the earth

6. Vector Even distances need reference points Need to say how many km from what point - may use words like “up”, “down”, “east”, “west”, etc. Vector is a quantity that shows both a magnitude (amount) and a direction - Represented by an arrow Scalar is a quantity that shows amount but not direction

7. Example For each below indicate if it is a vector or scalar quantity: 1) 5 m 2) 30 m/s East 3) 256 bytes 4) 5 mi North 5) 20 o C above freezing 6) 4000 calories

8. Displacement vs Distance Displacement of an object is defined as a change in position – it is a vector Distance is not a vector A person walks 70m east and then turns around and walks 30m west a) what is the total distance traveled b) what is the displacement

9. Position A coordinate axis is often used to show a frame of reference from the zero point Objects right of the zero have a positive value while those to the left are negative - positive and negative signs indicate direction The position of the object is given by the x coordinate

10. Equation Displacement is the the ending position minus the starting position Δx = x 1 - x 0 A person starts at the +30 km mark and then walks to the +10 km mark, what is their displacement

11. Example Consider a football coach pacing back and forth along the sidelines. The diagram below shows several of coach's positions at various times. At each marked position, the coach makes a "U-turn" and moves in the opposite direction. In other words, the coach moves from position A to B to C to D. What is the coach’s displacement and distance of travel?