Question

Rachel is a stunt driver, and she's escaping from a building that is about to explode!

The variable d models Rachel's distance from her exit (in meters) t seconds after the cameras began recording the stunt. d = -38t + 220. Whats Rachels Speed?
Meters per second

Answer 1

38 m/s

Explanation:

Velocity is the rate of change of distance with time.

.. dd/dt = -38 . . . . meters per second

Speed is the magnitude of velocity.

... |-38| = 38 . . . . meters per second

_____

Comment on Rachel's distance

Since the distance is decreasing with time, we have to assume that it is measured inside the building, and that negative distance means distance outside the building.