A bird is tossing (flying to and fro) between two cars moving towards each other on a straight road. One car has a speed of `18 km //h` while the other has the speed of ` 27 km //h`. The bird starts moving from first car towards the other and is moving with the speed of ` 36 km //h` and when the two cars were separated by ` 36 km`. What is the total distance covered by the bird ? What is the total displacement of the bird ?

Options

A. 28.8 km
B. 38.8 km
C. 48.8 km
D. 58.8 km

Answer

A

Explanation

Velocity of car A, `v_A = +27 km h^(-1)`
Velocity of car B, `v_B = -18 km h^(-1)`
Relative velocity of car A with respect to car B
= `v_A - v_B = +27 km h^(-1) - (-18 km h^(-1)= 45 km h^(-1))`
Time taken by the two cars to meet = `(36 km)/(45 km h^(-1)) = 0.8`
= `36 km h^(-1) xx 0.8 h` = 28.8 km