Question

A bicycle rider traveling east at 10 km/hr sees a blue car pass her appearing to travel west at 50 km/hr. What is the blue car's apparent speed for an observer riding in a red car traveling 15 km/hr west relative to the Earth? g

Answer 1

`v_(bR) = 25 km/h` towards west

Step-by-step explanation:

As we know that the speed of the blue car as appear to the bicycle rider is given as

`v_(bc) = 50 km/h` towards west

also it is given that bicycle is moving at speed of 10 km/h towards East

so here we have

`v_(bc) = v_b - v_c`

so we have

`v_b = v_(bc) + v_c`

`v_b = -50 + 10 = 40 km/h` towards west

now speed of the red car is given as 15 km/h towards west

so here the relative speed of blue car with respect to red car is given as

`v_(bR) = v_b - v_R`

`v_(bR) = 40 - 15 = 25 km/h` towards west