Problem 2-62 - Distance and speed - Part 5

A truck travels at \(80 \;km/h\) for \(30 \;min\), then at \(60 \;km/h\) for \(1.5\; hr.\) Assuming 2 significant digits in the given numbers, calculate the truck's
(a) total distance traveled, and
(b) average speed.

Accumulated Solution

\(\mathrm{speed = \frac{d}{\Delta t }\\ d = (speed) \Delta t \\ d_1 = 40\; km}\)

The distance traveled at the second speed is:

(A)   \((60\; km/hr)(1.5\; hr) = 90\; km\)

(B)   \((60 \;km/hr)/(1.5\; hr) = 40\; km\)

(C)   \((60 \;km/hr)(90\; min) = 1500\; km\)