A car A is going north-east at 80km/h and another car B is going south...
Given:Car A is going north-east at 80 km/h
Car B is going south-east at 60 km/h
To find:The direction of the relative velocity of car A with car B makes an angle x with north. Find tan x.
Solution:Let us consider the two cars A and B as shown in the figure below:
The velocity of car A can be resolved into two components:
1. Velocity towards north = 80/sqrt(2) km/h (since it is moving at 45 degrees to the north direction)
2. Velocity towards east = 80/sqrt(2) km/h (since it is moving at 45 degrees to the east direction)
Similarly, the velocity of car B can be resolved into two components:
1. Velocity towards south = 60/sqrt(2) km/h (since it is moving at 45 degrees to the south direction)
2. Velocity towards east = 60/sqrt(2) km/h (since it is moving at 45 degrees to the east direction)
The relative velocity of car A with respect to car B can be found by subtracting the velocity of car B from the velocity of car A:
1. Velocity towards north-east = (80/sqrt(2) - 60/sqrt(2)) km/h = 20/sqrt(2) km/h
The direction of the relative velocity of car A with respect to car B makes an angle x with north. This angle can be found as follows:
tan x = (Velocity towards north-east) / (Velocity towards north)
tan x = (20/sqrt(2)) / (80/sqrt(2))
tan x = 1/4
tan x = 0.25
Therefore, the direction of the relative velocity of car A with respect to car B makes an angle of tan^-1(0.25) with north.