Kinematics

1
Kinematics

• Goals understand graphs of
• a) position versus time,
• b) velocity versus time.

2
Basic concepts in kinematics

• Position
• Displacement
• Speed
• Average Velocity
• Instantaneous velocity

3
Graphs position Versus time.

• Describe the motion
• of the person.

4
Q1. Distance and Displacement

• A person travels from one point A in space to
  another point B. The magnitude of the
  displacement is
• either greater than or equal to
• always greater than
• always equal to
• either smaller than or equal to
• the distance traveled.

5
Graphs position versus time.

• Calculate the average velocity from such a
  graph.

6
Graphs position Versus time.

• Instantaneous velocity versus time
• local slop

7

• Q2 At which point, the
• velocity is zero ?
• P1
• P2
• 3) P3
• 4) P4.

8
Graphs velocity versus time

• How to calculate the displacement from such a
  graph?

9
Finding position from velocity

• Displacement is equal
• to the area below
• a velocity curve.
• The area is positive if the curve is above
• v0 axis negative if below the axis.

10
Motion of a car.

• A person is driving northward along the east
  mall Blvd with an initial velocity 10m/s starting
  from in front of the Hebb theatre.
• 1) Where is the turning point?
• 2) Where is the person at t6s?

11
Q3 (do it at home)

• The average velocity and average speed between
  t0 and 6s in this case are, respectively,
• 10m/s and 15m/s
• 8.33 m/s and 8.33 m/s
• - 5m/s and 8.33m/s
• -5m/s and - 8.33m/s.