linear kinematics displacement velocity and acceleration wod are underlined
TRANSCRIPT
Linear Kinematics
Displacement Velocity and Acceleration
WOD are underlined
Linear KinematicsKinematics = “ 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 = af – ai
• Δd = change in d = df – di
• Δv = change in v = vf – vi
• 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)
• 5m @ 0 degrees.
Displacement
The displacement x is a vector that points from the initial position xi to the
final position xf. x = xf - xi
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 * 1011 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 * 1011 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 * 1011 = 4.7 * 1011 m
• What is the displacement?
• Twice the radius = 2 *1.5* 1011 = 3.0 * 1011 m
Question:
• The Earth is 1.5 * 1011 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 * 1011 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 * 1011 = 9.4 * 1011 m
• What is the displacement?
• 0. It has made a full circle to its starting point