# Traveling problem

• Jun 26th 2006, 07:18 PM
Dora
Traveling problem
While you are traveling in a car on a straight, level inter-state highway at 90 km/h, another car passes you in the same direction; its speedometer reads 120 km/h. (a) What is your velocity relative to the other driver? (b) What is the other car's velocity relative to you?
• Jun 27th 2006, 08:38 AM
CaptainBlack
Quote:

Originally Posted by Dora
While you are traveling in a car on a straight, level inter-state highway at 90 km/h, another car passes you in the same direction; its speedometer reads 120 km/h. (a) What is your velocity relative to the other driver? (b) What is the other car's velocity relative to you?

Your velocity relative to the other driver is \$\displaystyle v_y-v_o\$, where
\$\displaystyle v_y\$ is your velocity, and \$\displaystyle v_o\$ is the other driver's velocity. So:

a) 90-120 = -30 km/hr

The other cars velocity with respect to you is \$\displaystyle v_o-v_y\$, so:

b) 120-90 = 30 km/hr.

RonL