Linear Kinematics Displacement Velocity and Acceleration WOD are underlined

Linear Kinematics Kinematics = “ the study of motion” Forms of Motion 1. Linear translation all points on the body move the same distance in the same direction in the same amount of time 2. Angular rotation 3. General translation and rotation

Linear Kinematics Kinematics = “ the study of motion” Forms of Motion 1. Linear Translation 2. Angular rotation

New Terms Distance – length of path travelled. Scalar (number only.) In meters Displacement- Change in position from start to stop. Vector (number and direction.) Also in meters Walk around desk. How far did you go?

Distance What is the distance traveled in this picture?

Distance What is the displacement of the person in this picture?

Distance What is the displacement of the person in this picture? Displacement: DOES NOT CARE ABOUT PATH. START TO STOP!!!

Where is 0 degrees for a Vector? Is 0 Deg always +X??? No. +X = 0 Deg or East -X = 180 Deg -Y = 270 Deg +Y = 90 Deg

Negative Displacement What does positive vs negative: Mean for Distance? Mean for Displacement? 5m at 37 ° -5m at 37 °

Distance and Displacement Starting from origin O, a person walks 90-m east, then turns around and walks 40-m west. Q: What is the total walked distance?

Distance and Displacement Starting from origin O, a person walks 90-m east, then turns around and walks 40-m west. Q: What is the total walked distance? A: 130-m

Distance and Displacement Starting from origin, O a person walks 90-m east, then turns around and walks 40-m west. Q: What is the total walked distance? A: 130-m Q: What is the displacement?

Distance and Displacement Starting from origin, O a person walks 90-m east, then turns around and walks 40-m west. Q: What is the total walked distance? A: 130-m Q: What is the displacement? A: 50-m, due east. (or at 0 deg)

New Symbol Δ – “Delta” Means “change in” Final value – initial value Δa = change in a = a f – a i Δd = change in d = d f – d i Δv = change in v = v f – v i Etc.

New Symbol So: x is horizontal position Δx is “change in x” Δx is “horizontal displacement” Δy is “vertical displacement”

If someone is at x = 5, What distance have they traveled? (start at origin)

If someone is at x = 5, What displacement have they traveled? (start at origin) +X = 5

If someone is at x = 5, What displacement have they traveled? (start at origin) 0 degrees.

Displacement The displacement  x is a vector that points from the initial position x i to the final position x f.  x = x f - x i SI Unit of Displacement: meter (m) and direction (angle in radians or deg).

What is a radian??? +X = 0 or 2 π or East -X = π -Y = 3π/2 +Y = π/2

Question: The Earth is 1.5 * meters from the sun. 1.) If the orbit is a perfect circle, what is the distance the earth moves in six months? 2.) What is the displacement?

Question: The Earth is 1.5 * meters from the sun. If the orbit is a perfect circle, what is the distance the earth moves in six months? 1 half orbit = 2  r /2 = (3.14)* 1.5 * = 4.7 * m What is the displacement? Twice the radius = 2 *1.5* = 3.0 * m

Question: The Earth is 1.5 * meters from the sun. If the orbit is a perfect circle, what is the distance the earth moves in twelve months? What is the displacement?

Question: The Earth is 1.5 * meters from the sun. If the orbit is a perfect circle, what is the distance the earth moves in twelve months? 1 full orbit = 2  r = 2*(3.14)* 1.5 * = 9.4 * m What is the displacement? 0. It has made a full circle to its starting point