Notes: Week 15 - Position vs Time graphs

Notes: Week 15 - Position vs Time graphs

Topics covered:

• Describing motion on a position vs time graph
• How to calculate velocity on a position vs time graph

Position vs Time graphs = show an object’s movement

• position (x) is on the y-axis
• time (t) is on the x-axis

• Objects at rest: will form a straight horizontal line

Position vs Time graphs (x vs t)

• Starting position of object: where the y-intercept is located (can be positive or negative)

Position vs Time graphs (x vs t)

How calculate velocity?

• The slope of a position vs. time graph represents velocity

Slope = change in position / change in time

• Commonly measured in meters/second (m/s)

Velocity tells you two things about the motion of the object

• How fast (m/s)
• What direction (+/-)

Data Analysis

What is happening at: t = 0 to 5? t = 5 to 10? t = 10 to 12.5?

Data Analysis

What is happening at: t = 0 to 5? Moving at constant speed in positive direction t = 5 to 10? Not moving t = 10 to 12.5? Moving at a constant speed in negative direction

Data Analysis

Velocity at: t = 0 → 5? t = 5 → 10? t = 10 → 12.5? t = 0 → 12.5 secs?

Data Analysis

Calculate the slope! Velocity at: t = 0 → 5? 5/5 = +1m/s t = 5 → 10? = 0/5 = 0 m/s t = 10 → 12.5? = -5/2.5 = -2m/s t = 0 → 12.5 secs? = 0/12.5 = 0m/s