Question

question 3 of 10
car 1 drives 35 mph to the east, and car 2 drives 50 mph to the west. from the frame of reference of car 1, what is the velocity of car 2?
a. 15 mph west
b. 15 mph east
c. 85 mph east
d. 85 mph west

Explanation:

Step1: Define positive - direction

Let the east - direction be positive. So the velocity of car 1, $v_1 = 35$ mph and the velocity of car 2, $v_2=- 50$ mph.

Step2: Calculate relative velocity

The relative velocity of car 2 with respect to car 1, $v_{21}=v_2 - v_1$. Substitute the values: $v_{21}=-50 - 35=-85$ mph. The negative sign indicates the west - direction.

Answer:

D. 85 mph west