An object starts at position x = +10 meters. It moves at +5 m/s for 10 seconds then (instantly! magically!) changes its velocity to -10 m/s for the next 10 seconds.

Question

An object starts at position x = +10 meters. It moves at +5 m/s for 10 seconds then (instantly! magically!) changes its velocity to -10 m/s for the next 10 seconds.

1. Draw a graph showing the object's position as a function of time.
2. Draw a graph showing the object's velocity as a function of time.
3. What is the object's displacement? Use a fact + connection to explain how you know the displacement.

Answer 1

At t = 0, x = 10

At t = 10, x = 10 + (5)(10) = 60

At t = 20, x = 60 + (-10)(10) = -40

From t = 0 to t = 10, v = 5

From t = 10 to t = 20, v = -10

So the graphs would look like this:

Displacement is the net distance traveled. So, it started at x = 10 and ended at x = -40 so the displacement is -40 - 10 = -50 meters