Question

question 9 of 25
the diagram below shows the velocity vectors for two cars that are moving relative to each other.
25 m/s west car 1
20 m/s west car 2
from the frame of reference of car 2, what is the velocity of car 1?
a. 45 m/s east
b. 20 m/s west
c. 5 m/s west
d. 5 m/s east

Explanation:

Step1: Define relative - velocity formula

The formula for relative velocity of car 1 with respect to car 2 is $v_{12}=v_1 - v_2$, where $v_1$ is the velocity of car 1 and $v_2$ is the velocity of car 2. Let the west - direction be negative. So, $v_1=- 25\ m/s$ and $v_2=-20\ m/s$.

Step2: Calculate relative velocity

Substitute the values into the formula: $v_{12}=-25-(-20)=-25 + 20=-5\ m/s$. The negative sign indicates the direction is west.

Answer:

C. 5 m/s west