Explore BrainMass
Share

# Determining a constant speed based on previous and average speed

This content was COPIED from BrainMass.com - View the original, and get the already-completed solution here!

A motorist makes a trip of 180 miles. For the first 90 miles, she drives at a constant speed of
30 mph. At what constant speed must she drive the remaining distance, if her average speed for
the total trip is to be 40 mph?

© BrainMass Inc. brainmass.com March 21, 2019, 11:17 pm ad1c9bdddf
https://brainmass.com/physics/classical-mechanics/determining-constant-speed-based-previous-average-speed-452172

#### Solution Preview

The average speed for the whole trip is simply given by:

Va = DISTANCE TRAVELED/TIME TAKEN = D/T

Va = average speed, D = distance traveled (total), T = total time traveled.

It is easy to think that

Va = (v1+v2)/2, but this is incorrect, use the formula above. From the problem we can ...

#### Solution Summary

This solution explains how to determine a constant speed based on previous and average speeds.

\$2.19